bluuebunny/crossref_metadata_2025 huggingface dataset:
Demonstration that nonspecific bovine Brucella abortus agglutinin is EDTA-labile and not calcium-dependent.
Authors: Nielsen K , Duncan J R
Published: December 2022

The binding site of B. abortus involved in nonspecific or false-positive agglutination by bovine serum was shown to be Ca++-independent in that binding of Ca++ by the chelating reagent DP2TA did not decrease titers. The reduction in agglutination by EDTA, EGTA, and DPTA was thought to be related to a common structural characteristic of these chelating reagents not exhibited by EDDA and DP2TA or to a lesser extent by DTPA. Removal of antigenic entities from the cell by the chelator was excluded as the cause of agglutination inhibition because agglutination by nonspecific IgM was not influenced by repeated washing of B. abortus by EDTA. The action of the chelators on the cell-agglutinin interaction was hypothesized to be a result of their competition with a receptor site on the cell for binding of the nonspecific or biochemically altered bovine IgM.
Differentiation and activation of nu/nu splenic T cell precursors by mature peripheral T cells in the absence of thymus.
Authors: Lipsick J S , Serunian L , Sato V L , Kaplan N O
Published: December 2022

Nu/nu splenic T cell precursors lacking significant Thy-1 surface antigen are driven in vitro to proliferate and express Thy-1 during incubation with activated, nondividing peripheral T cells in the absence of thymus or thymic extracts. The precursors are present in nu/+ spleen as well, and are phenotypically similar to thymocyte precursors assayed in vivo. The nondividing inducer cells required are Lyt-2-, Thy-1+ T cells present in nu/+ but not nu/nu spleen and show no MHC restriction in the induction process. Using this in vitro assay, we preliminarily identified a monoclonal rat anti-mouse brain antibody that lyses nu/nu responding T cell presursors in the presence of complement. The ability of mature peripheral T cells to induce the differentiation and activation of T cell precursors in the complete absence of thymus appears to explain the grossly different effects of neonatal and adult thymectomy or thymic involution on immunocompetence. In addition, we showed that the limiting cell in three-cell mitogenic response of normal spleen cells to Con A is likely the macrophage by similar analysis of nondividing inducer cell requirements. This finding allows the assignment of a unique order to this three-cell response.
Functional properties of T cells in patients with chronic T gamma lymphocytosis and chronic T cell neoplasia.
Authors: Rümke H C , Miedema F , ten Berge I J , Terpstra F , van der Reijden H J , van de Griend R J , de Bruin H G , von dem Borne A E , Smit J W , Zeijlemaker W P , Melief C J
Published: December 2022

The expanded T cell populations of 10 patients with either T gamma lymphocytosis (five patients) or proven chronic T cell malignancy (five patients) were analyzed with respect to functional activity in vitro, including proliferative responses to mitogens, cytotoxic activity (killer [K] and natural killer [NK] cell activity), and regulatory activity on pokeweed mitogen- (PWM) induced immunoglobulin (Ig) synthesis (help and suppression) in comparison with marker phenotypes. In each of the five patients with T gamma lymphocytosis, only one out of three functionally distinct cell types was found: T gamma-K cells, T gamma-S cells, or T gamma-NK/K cells, which mediated K-cell activity, suppressive activity, and both NK and K cell activity, respectively. An expanded T gamma-K cell population was demonstrated in three patients with neutropenia with or without recurrent infections. T gamma-S cells were found in a patient with severe hypogammaglobulinemia, and T gamma-NK/K cells in one patient with asymptomatic lymphocytosis. T gamma-K and T gamma-S cells had a similar surface-marker profile (E+ or E-, Fc gamma+, OKT1-3+4-8+I1-M1-), whereas that of T gamma-NK/K cells was different (E+, Fc gamma+, OKT1-3-4-8-I1+M1+). Longitudinal studies of three untreated patients with T gamma-K lymphocytosis showed that the abnormalities were persistent but not progressive. In contrast, five patients with chronic T cell malignancy (two with T-CLL, two with cutaneous T cell lymphoma [CTCL], and one with T-PLL) all had progressive disease. The neoplastic cells in these cases were E+, Fc gamma-OKT1+4+6- with variable expression of the OKT3 and OKT8 markers. The only functional activity observed in these cells was suppressive activity by OKT3-4+8- cells from a patient with CTCL.
T cell-independent responses to an Ir gene-controlled antigen. I. Characteristics of the immune response to insulin complexed to Brucella abortus.
Authors: Thomas J W , Bucy R P , Kapp J A
Published: December 2022

Immune responses by mice to heterologous insulins are controlled by H-2-linked Ir genes. Antibody responses to insulin are T cell dependent (TD), and nonresponder mice fail to make detectable insulin-specific antibodies. To further analyze the role of T cells in regulation of immune responses to insulin, we have developed a method for induction of insulin-specific B cells in the relative absence of T cells. Insulin has been chemically coupled to the T cell-independent (TI) organism Brucella abortus (insulin-BA). Studies reported here demonstrate that in terms of kinetics of responses, isotype expression, and induction of responses in X-linked immunodeficient mice, insulin-BA behaves as a typical type-1 TI antigen. Despite these characteristic features, T cells appear to augment the response to insulin-BA. More importantly, insulin-BA stimulates IgM and IgG anti-insulin antibodies in all strains tested regardless of whether the mice were responders or nonresponders to the particular insulin tested. Thus insulin-BA should be a useful antigen for dissecting the cell interactions required for development of insulin-specific immunity.
The role of three distinct Ia-like antigen molecules in human T cell proliferative responses: effect of monoclonal anti-Ia-like antibodies.
Authors: Koide Y , Awashima F , Yoshida T O , Takenouchi T , Wakisaka A , Moriuchi J , Aizawa M
Published: December 2022

Murine monoclonal antibodies (MoAb) to three distinct Ia-like molecules were studied for their inhibitory effects on antigen- and alloantigen-induced T cell proliferations. The MoAb were classified into three groups according to the molecules they recognized. Both the group I MoAb reacting with DR molecules and the group III MoAb were capable of inhibiting T cell proliferative responses to PPD- and HSV-Ag-pulsed APC, autologous B-LCL, and alloantigens. On th other hand, the group II MoAb, which reacted with a determinant on the molecule carrying MB1 determinants, was only capable of inhibiting T cell responses to alloantigens. These results suggest that the structure of the molecules correlates with the functional repertoire of the human Ia-like antigens.
A predominant idiotype on rabbit anti-VH a1 allotype antibodies: sharing by both major and minor VH subgroups.
Authors: Metzger D W , Roux K H
Published: December 2022

In every rabbit examined, greater than or equal to 80% of antibodies directed against the VH allotypic marker, a1, bears a predominant idiotype (IdX-a1). The IdX-a1 marker is site-associated and expressed on H chains, but not L chains, of anti-a1 antibody. Experiments using rabbits suppressed for the VH a subgroup demonstrated that IdX-a1 can be associated with both major (a+) and minor (a-) VH subgroup gene products and that a1 rabbits contain IdX-a1 within their genetic repertoire. The genetic and regulatory implications of our results are discussed.
Human alveolar macrophages: potentiation of their tumoricidal activity by liposome-encapsulated muramyl dipeptide.
Authors: Sone S , Tsubura E
Published: December 2022

Homogeneous preparations of human alveolar macrophages (AM) were obtained by bronchoalveolar lavage of the lungs of healthy nonsmokers. These AM exhibited a low level of spontaneous cytolytic activity against allogeneic A375 melanoma cells. Tumoricidal activity of AM could be generated and/or augmented by incubation in vitro with either lipopolysaccharides (LPS) or muramyl dipeptide (MDP). MDP derivatives were encapsulated within multilamellar (MLV) liposomes composed of phosphatidylcholine-phosphatidylserine (PC/PS). Dose-response experiments established that liposome-encapsulated MDP augmented the tumoricidal activity of AM at concentrations about 100 times lower than free MDP in the medium. AM activated by MLV containing MDP destroyed allogeneic tumor cell lines, but did not affect cultures of normal, non-neoplastic cells. An inactive derivative, MDP-L, encapsulated in MLV liposomes did not potentiate the tumoricidal activity of AM. We conclude that human AM respond to MDP in vitro and that liposomes containing MDP are far more efficient than unencapsulated, free MDP for enhancing the tumoricidal activity of human AM.
Antibodies from the Lyb-5- B cell subset predominate in the secondary IgG response to phosphocholine.
Authors: Wicker L S , Guelde G , Scher I , Kenny J J
Published: December 2022

The X-linked CBA/N immune defect was used to investigate the role of the Lyb-5- B cell subset in phosphocholine- (PC) specific memory responses. Immune-defective mice, which express only the Lyb-5- B cell subset, are unable to mount a primary or secondary T15+, IgM response to PC but can produce a substantial secondary IgG response. The majority of these IgG anti-PC antibodies are T15- and can be inhibited by phenylphosphocholine, but not PC. Normal mice, which possess Lyb-5+ and Lyb-5- B cells, produce both IgM and IgG anti-PC antibodies; however, there is a striking difference in the idiotype and fine specificity of antibodies expressed by these two classes. The IgM anti-PC antibodies are T15+ and PC-inhibitable, whereas the IgG antibodies are identical to those observed in the immune-defective mice, i.e., T15- and PC-noninhibitable. This unexpected difference in both idiotype and fine specificity between IgM and IgG anti-PC antibodies results from activation of different B cell subsets. Lyb-5+ B cells produce T15+, PC-inhibitable IgM antibodies, whereas T15-, PC-noninhibitable IgG antibodies are produced by Lyb-5- B cells. These data indicate that a majority of the thymus-dependent, anti-PC IgG memory responses arises from Lyb-5- B cells.
The specificity of the syngeneic mixed leukocyte response, a primary anti-I region T cell proliferative response, is determined intrathymically.
Authors: Glimcher L H , Schwartz R H , Longo D L , Singer A
Published: December 2022

In previous studies, the syngeneic MLR of peripheral T cells was shown to be predominantly an I region-restricted function. In this report we show that adult thymocytes are also capable of responding to syngeneic irradiated stimulator cells in a syngeneic MLR, provided that TCGF is added to the culture system. Using this assay, it was possible for the first time to examine the pattern of I region restriction within the thymus itself. Analysis of the thymocyte syngeneic MLR in thymuses from radiation-induced bone marrow chimeras demonstrated that the MHC preference seen in the peripheral T cell population also existed in cells resident within the thymus. Experiments utilizing congenitally athymic mice transplanted with allogeneic thymic grafts demonstrated that both peripheral T cells and thymocytes from such animals displayed a strong preferential proliferation toward stimulator cells bearing thymic-type MHC determinants. The results in the nude model thus demonstrate that the thymus by itself is sufficient to impart such restriction specificity on a developing T cell repertoire. These results are consistent with the notion that the thymus exerts selective pressure on maturing T cell populations that results in a skewing of the T cell repertoire toward the recognition of thymic-type I region products, and that this MHC preference exists before expansion of T cells in the periphery.
Detection of IgG bound within human trophoblast.
Authors: Wood G W , Bjerrum K , Johnson B
Published: December 2022

Previous studies have failed consistently to detect either binding sites for exogenous IgG or endogenous IgG on human trophoblast by using conventional immunohistologic methods. The present study demonstrates specific binding sites for exogenous IgG on all trophoblast-derived cells. The binding sites were detectable with monomeric IgG but not IgG aggregates. The binding sites were detected more easily if cells were washed at an acid pH (5.0). The level of binding activity was greater in younger placental tissue, although expression of binding sites on cells in extraplacental membranes was age-independent. Complexing of bound exogenous IgG resulted in its dissociation from tissue binding sites. Endogenous trophoblast-associated IgG was readily detectable when anti-IgG reagents that produced minimal complexing were used, e.g., Fab fragments of rabbit antihuman IgG. High levels of both Fc gamma binding sites and endogenous IgG were detected in placentae as late as 30 wk gestation, but both were present only in low levels at term. The results demonstrate that both binding sites for exogenous and endogenous IgG are associated with the human trophoblast and support the theory that IgG transport through the human trophoblast is dependent on Fc gamma receptors.
Characterization of alloimmune memory in a sponge.
Authors: Bigger C H , Jokiel P L , Hildemann W H , Johnston I S
Published: December 2022

Alloimmune memory, revealed by consistently accelerated second-set graft rejection in contrast to unrelated third-party reactions, has been reported in four species of marine sponge. Allogeneic tissue of the marine sponge, Callyspongia diffusa was grafted/parabiosed to examine critically the essential features of alloimmune memory in this member of the least complex major metazoan phylum. Although sponges lack an organized circulatory system, the immunologic memory spreads rapidly through body tissues. Heightened reactivity persisted for only 3 yo 4 wk after primary sensitization. This appears to constitute a major difference from the long-term alloimmune memory found among vertebrates. This limited duration of memory, however, is apparently sufficient for the individual sponge to cope with repeated challenges to its integrity.
Specific binding of leukotriene B4 to receptors on human polymorphonuclear leukocytes.
Authors: Goldman D W , Goetzl E J
Published: December 2022

Leukotriene B4 (5(S),12(R)-di-hydroxy-eicosa-6,14-cis-8,10-trans-tetraenoic acid [LTB4]) is a product of the 5-lipoxygenation of arachidonic acid, which elicits human PMN leukocyte chemotactic responses in vitro that are 50% of the maximal level at concentrations of 3 X 10(-9) M to 10(-8) M and are maximal at 2 X 10(-8) M to 10(-7) M. The specific binding of highly purified [3H]LTB4 to human PMN leukocytes was assessed both by extracting the unbound and weakly bound [3H]LTB4 with acetone at -78 degrees C and by centrifuging the PMN leukocytes through cushions of phthalate oil to separate the unbound from bound [3H]LTB4. The levels of total binding of [3H]LTB4 and of nonspecific binding of [3H]LTB4, in the presence of a 1500-fold molar excess of nonradioactive LTB4, were approximately two times higher with the phthalate oil method. Scatchard plots of the concentration dependence of the specific binding (total - nonspecific binding) of [3H]LTB4 to PMN leukocytes were linear for the acetone extraction and phthalate oil methods and revealed dissociation constants of 10.8 X 10(-9) M and 13.9 X 10(-9) M, respectively, and mean of 2.6 X 10(4) and 4.0 X 10(4) receptors per PMN leukocyte. The 5(S),12(S)-all-trans-di-HETE analog of LTB4 and 5-HETE competitively inhibited by 50% the binding of [3H]LTB4 to PMN leukocytes at respective concentrations that evoked half-maximal chemotactic responses, whereas neither N-formyl-methionyl-leucyl-phenylalanine nor chemotactic fragments of C5 inhibited the binding. Human erythrocytes exhibited no specific binding sites for [3H]LTB4. Human PMN leukocytes possess a subset of receptors for LTB4 that are distinct from those specific for peptide chemotactic factors.
Opsonization of encapsulated Staphylococcus aureus: the role of specific antibody and complement.
Authors: Verbrugh H A , Peterson P K , Nguyen B Y , Sisson S P , Kim Y
Published: December 2022

Previous studies of encapsulated Staphylococcus aureus have shown that the opsonins of normal, nonimmune human serum (complement factor C3 and IgG) bind beneath the capsule, i.e., on the cell wall, and when bound at this site these opsonins are not effective in promoting phagocytosis of the bacteria by polymorphonuclear leukocytes (PMN). In this investigation immune antibody was added to human serum to effect opsonization of encapsulated S. aureus. Opsonization was assessed by quantitating the uptake of 3H-labeled staphylococci by human PMN, and the amount of C3 fixation to bacteria was measured in a quantitative fluorescent immunoassay. Low levels of immune antibody (IgG) effectively opsonized encapsulated S. aureus when added to fresh but not to heated serum; phagocytosis of the staphylococci was mediated via pronase-sensitive membrane receptors (presumably C3b receptors) of PMN. Experiments with C2-, C3-, or C5-deficient human sera revealed that C3 was required for opsonization and that activation of C3 was mediated via the alternative complement pathway. Encapsulated S. aureus bound significantly less C3 than unencapsulated strains in diluted normal serum; addition of immune antibody, however, increased C3 fixation 4.7-fold (p less than 0.005). Immunoelectron microscopy localized C3 throughout the capsule as well as on the staphylococcal cell wall when bacteria had been opsonized in human serum with immune antibody. Without immune antibody, C3 binding was restricted to the cell wall. At approximately 10-fold higher levels of immune antibody, opsonization and phagocytosis of encapsulated S. aureus was independent of complement and pronase-sensitive receptors on PMN. These studies show that, in addition to immune antibody, the alternative pathway of complement plays an important role in the opsonization of encapsulated S. aureus strains and suggest that complement may be crucial to the in vivo clearance of these organisms.
Helper cell function of Leukemic Leu-2a+, histamine receptor+, T gamma lymphocytes.
Authors: Siegal F P , Rambotti P , Siegal M , Lopez C , Smith M , Davies T F , Osband M , Estren S
Published: December 2022

Leukemic cells from a patient with an 11-yr history of chronic lymphocytic leukemia (CLL) were found to have the surface phenotype Leu-1+, Leu-2a+, Leu-3a-, sheep erythrocyte rosette+, IgGFc receptor+. The cells also bore a receptor for histamine inhibitable by cimetidine (H-2). The clonal nature of the proliferation was documented by the presence of a consistent marker chromosome (22-trisomy) in metaphases elicited by culture with T cell growth factors. Although the surface phenotype suggested that these cells might function as suppressor lymphocytes, they had an enhancing effect on the pokeweed- mitogen- (PWM) driven generation of plasma cells and reverse hemolytic plaque-forming cells in vitro. This helper activity was modified neither by irradiation of the leukemic cells nor by removal of a minor population of Leu-3a+ cells, suggesting that the effects were attributable to the CLL cells themselves. In addition to these functions, the CLL cells were active in antibody-dependent cellular cytotoxicity (ADCC) assays in association with expression of Fc receptors for IgG. The ADCC was diminished when a transient loss of the Fc receptor expression was observed. No activity in natural killer cell assays employing K-562 cells or herpes simplex virus- (HSV) infected cells as targets could be attributed to the leukemic clone. These studies indicate that the cell surface phenotype, as defined by monoclonal antibodies, may not always predict the functional state of a particular cell, and suggest that within the Leu-2a+ (TH-2+) population of human lymphocytes, some helper as well as suppressor/cytotoxic cells are to be found.
Effect of cyclosporin A on T cell function in vitro: the mechanism of suppression of T cell proliferation depends on the nature of the T cell stimulus as well as the differentiation state of the responding T cell.
Authors: Dos Reis G A , Shevach E M
Published: December 2022

We have studied the effects of the immunosuppressive agent cyclosporin A (CY A) on T cell activation in the guinea pig both in the presence and in the absence of exogenous interleukin 2 (IL 2). CY A suppressed T cell activation by the mitogen, concanavalin A, by blocking IL 2 production and not by blocking the induction of IL 2 receptors. In contrast, the primary T cell proliferative responses to self-Ia antigens in the syngeneic mixed leukocyte reaction (SMLR) and to trinitrophenyl-modified syngeneic macrophages were blocked by CY A and this suppressive effect could not be corrected by addition of exogenous IL 2. T cells primed to syngeneic stimulator cells in the presence of CY A failed to develop IL 2 responsiveness even in the presence of exogenous IL 2, suggesting that CY A directly blocked induction of IL 2 receptors on the responding T cell population. In contrast, the secondary SMLR was suppressed by CY A in the absence of IL 2, but was normal when IL 2 was added to the cultures. CY A completely blocked the primary allogeneic MLR but this inhibitory effect could be reversed when exogenous IL 2 was added to the cultures. Moreover, in the presence of exogenous IL 2, CY A had no effect on the development of IL 2 responsiveness by alloreactive T cells. In addition, CY A induced a population of radiosensitive cells with suppressor activity for the primary MLR. Thus, in the guinea pig, CY A inhibits Ti cell activation both by blocking IL 2 production as well as by inhibiting the induction of IL 2 responsiveness. These two effects occur in the same range of CY A concentrations and are differentially dominant depending on the nature of the stimulating signal and the differentiation state of the responding T cell.
Immune serum transfer of cutaneous basophil-associated resistance to ticks: mediation by 7SIgG1 antibodies.
Authors: Brown S J , Graziano F M , Askenase P W
Published: December 2022

Guinea pigs acquired resistance to Amblyomma americanum larval ticks after one infestation, resulting in 46% tick rejection when challenged. Intravenous transfer of immune serum from twice-infested hosts to naive animals conferred a significant level of immunity resulting in 18 to 30% tick rejection. The minimum effective dose of serum was 3 ml per recipient, and heating the serum at 56 degrees C for 4 hr had no effect on serum activity. Fractionation of whole immune serum by gel filtration chromatography (Sephadex G-200) and ion -exchange chromatography (DEAE) demonstrated resistance activity to be in the IgG- and IgG1-containing fractions, respectively. Passage of whole immune serum through a heavy chain-specific rabbit anti-guinea pig IgG1 affinity column removed anti-tick activity and decreased the cutaneous basophil response to tick feeding by 70% in recipients. The ability to transfer both resistance to tick feeding and a significant cutaneous basophil response was eluted from the affinity column with 0.2 M Na2CO3, pH 11.5. In addition, immune serum raised against larval Ixodes dammini ticks, but not larval Rhipicephalus sanguineus ticks, was also effective at reducing feeding by larval Amblyomma americanum ticks, indicating that antibodies mediating resistance can be cross-reactive with antigens of different tick species and genera. This study demonstrates that IgG1 antibodies are responsible for the ability of immune serum to transfer cutaneous basophil-associated immune resistance against tick feeding in guinea pigs.
Maturational state of lymphoid cells in long-term bone marrow cultures.
Authors: Dorshkind K , Phillips R A
Published: December 2022

B lymphocytes are not produced in long-term bone marrow cultures (LTBMC) and controversy exists regarding T cell differentiation in the cultures. By analyzing the kinetics of B cell reconstitution in lethally irradiated mice by cells from fresh bone marrow or from LTBMC, we have determined that B cell differentiation is blocked at an early stage in the cultures. Colony-forming B cells (CFU-B) are generated more rapidly and to higher levels in recipients of fresh bone marrow cells than in animals grafted with cells from LTBMC. The data further indicate that the adherent fraction cells from LTBMC are an enriched source of B cell precursors as compared to non-adherent cells and that B cell reconstitutive potential and levels of spleen colony-forming stem cells (CFU-S) do not correlate with one another. Under appropriate culture conditions, T lymphocytes are detectable in LTBMC. These Thy-1-positive cells proliferate in the cultures and can generate cytotoxic responses. These effectors originate from Thy-1-positive cells present in the initial bone marrow inoculum used to establish the cultures and have not differentiated from mature Thy-1-negative progenitors in vitro.
Functional significance of Tac antigen expressed on activated human T lymphocytes: Tac antigen interacts with T cell growth factor in cellular proliferation.
Authors: Miyawaki T , Yachie A , Uwadana N , Ohzeki S , Nagaoki T , Taniguchi N
Published: December 2022

Cultured human T cells (CTC), which are grown in conditioned medium containing T cell growth factor (TCGF), proliferate in response to TCGF. It has been shown that an antigen (Tac) defined by a monoclonal antibody, termed anti-Tac antibody, is expressed on human T cells activated by mitogens or antigens and CTC grown in the presence of TCGF. To elucidate the functional significance of Tac antigen expressed on activated T cells, we studied the effect of anti-Tac antibody on TCGF-dependent proliferation of CTC. The addition of anti-Tac antibody strongly inhibited the proliferation of CTC induced by TCGF. This inhibition was observed only when the antibody was added at the early phase of culture, but not when the addition of the antibody was delayed beyond 24 hr of culture. Seven-day-old PHA-induced T cell blasts, but not fresh peripheral blood lymphocytes, were able to absorb TCGF activity in conditioned medium, as assessed by the DNA synthesis of CTC. When PHA-induced blasts were treated with anti-Tac antibody before absorption, their capacity to absorb TCGF activity was almost completely eliminated. In contrast, absorption of TCGF by PHA-induced blasts was not significantly reduced even when they were pretreated with other monoclonal antibodies (anti-Ia, OKT9, or OKT10) with specificity for antigens expressed on activated T cells. Based on the view that TCGF interacts with activated T cells via specific membrane receptors, these observations suggested that anti-Tac antibody might specifically block the binding of TCGF to the corresponding membrane binding sites, resulting in the inhibition of TCGF-dependent proliferation of CTC. Tac antigen expressed on activated T cells seems to participate in responding process of activated T cells to TCGF.
Suppression of human natural and antibody-dependent cytotoxicity by soluble factors from unstimulated normal lymphocytes.
Authors: Nair M P , Schwartz S A
Published: December 2022

Serum-free culture supernatants of unstimulated normal human peripheral blood mononuclear cells contain soluble suppressor factor(s) (SSF) that significantly inhibit natural (NK) and antibody-dependent cellular cytotoxic (ADCC) activities of allogenic lymphocytes against a variety of target cells. Lymphocytes precultured with increasing concentrations of SSF showed a dose-dependent suppressive effect on these cytotoxic functions that was optimal at a concentration of 20% volume/volume. Adherent cells were not required for the production of SSF. Suppression was evident even at higher effector: target cell ratios and the inhibition was not reversed by washing lymphocytes. SSF was not itself cytotoxic, was stable at 56 degrees C, and its suppressive effect was maximal after 72 hr of incubation with effector lymphocytes. Initial estimate of the molecular weight of SSF by ultra-filtration was less than 20,000 daltons. Gel filtration of SSF on Sephacryl S-200 resulted in the elution of two peaks of activity; one in the region between markers of 13,700 and 25,000 daltons, and the other less than 13,700 daltons. Both fractions demonstrated significant suppressive activity on NK and ADCC functions of allogenic lymphocytes. SSF inhibition of NK activity could be partially reversed by incubating lymphocytes for 1 hr with human leukocyte interferon (IF) and almost completely reversed after 24 hr of IF treatment. A few selected monosaccharides (alpha-methyl-D-mannoside, L-fucose and L-rhamnose) showed a dose-dependent blocking effect on SSF activity, which suggests that SSF may act via receptor sites recognized by these sugars. As demonstrated for other lymphocyte functions, NK and ADCC activities may also be modulated by SSF elaborated by normal PBL.
Differential expression of Ia glycoprotein complexes in F1 hybrid mice detected with alloreactive cloned T cell lines.
Authors: Conrad P J , Lerner E A , Murphy D B , Jones P P , Janeway C A
Published: December 2022

T cell lines alloreactive to Aeb:E alpha Ia antigen complexes have been prepared and used to determine the relative amount of Aeb:E alpha expressed by stimulator cells in homozygous recombinant and F1 mice expressing these complexes. We find that homozygous cells stimulate most strongly and therefore probably express the highest density of Aeb:E alpha. Among heterozygotes, H-2bxd F1 mice preferentially express Aeb:E alpha d complexes, H-2bxa F1 mice express relatively fewer Aeb:E alpha k complexes, and H-2bxu F1 mice express preferentially Aeu:E alpha u complexes. This differential association of Aeb chains with E alpha chains thus influences the biologic activity of these Ia antigens in this and other functional assays. The functional data are supported by biochemical analysis of Aeb:E alpha complex expression. These findings suggest that a reanalysis of HLA-DR associations with human diseases should be undertaken in which both HLA-DR alleles are included, with the prediction that certain combinations would show greater susceptibility, whereas others would show less susceptibility than predicted from the susceptibility associated with presence of a single allele at HLA-DR.
Determination of the protective epitopes on the glycoproteins of Venezuelan equine encephalomyelitis virus by passive transfer of monoclonal antibodies.
Authors: Mathews J H , Roehrig J T
Published: December 2022

We have previously characterized seven unique antigenic epitopes on the two envelope glycoproteins of the Venezuelan equine encephalomyelitis (VEE) virus vaccine strain, TC-83, by using monoclonal antibodies. The in vitro function of virus neutralization was primarily associated with one epitope on the gp56 (gp56c). To determine which epitopes were important in protecting animals from VEE infection, purified monoclonal antibodies were inoculated i.v. into 3-wk-old Swiss mice. Twenty-four hours later these animals were challenged i.p. with 100 IPLD50 of virulent VEE virus (Trinidad donkey). High-avidity anti-gp56c, anti-gp50b, anti-gp50c, and anti-gp50d monoclonal antibodies protected animals from virus challenge. Rabbit antisera to the gp56 and the gp50 glycoproteins were also effective in protecting mice from challenge with virulent VEE virus. Less antibody was needed to protect animals if the antibody was directed against the critical neutralization site. Less avid antibodies to the gp56c and gp50b epitopes demonstrated little or no protection in vivo. Protection, therefore, appeared to be a function of the passive antibody's specificity, avidity, and ability to bind to virion antigenic determinants topologically proximal to the critical neutralization site.
Depression of natural killer activity and mitogen responsiveness in mice treated with pristane.
Authors: Freund Y R , Blair P B
Published: December 2022

In BALB/c mice, the injection of pristane resulted in a severe decrease in splenic T and B cell proliferative responses to mitogens and in a depression of natural killer (NK) activity. The effects of T and B cells, which persisted for at least 5 mo, were mediated by different mechanisms. T cell responsiveness to PHA dropped significantly below control levels 1 wk after the first of three monthly pristane injections, whereas B cell proliferation in response to LPS did not decrease until 4 wk after the first injection. The removal of plastic-adherent suppressor cells completely restored T cell proliferative capacity, but had no effect on B cells. NK activity against YAC-1 tumor targets was reduced 1 mo after the first pristane injection and remained depressed for at least 3 mo. This depression was not mediated by plastic-adherent suppressor cells. Spleen cell NK activity from pristane-treated mice could not be augmented by the interferon inducer Poly I:C to the same extent as that of control mice. This suggests an effect of pristane on either pre-NK cells or on cells that regulate NK activity.
Cell surface phenotype of a cloned line of human natural killer cells.
Authors: Kornbluth J , Flomenberg N , Dupont B
Published: December 2022

A human cell line with strong natural killer (NK) activity lacking alloreactive cytotoxicity was derived from a primary mixed lymphocyte culture (MLC). The line was developed from a single colony grown in soft agarose and subsequently expanded in liquid culture. Several subcultures with identical reactivity were established, one of which (3.3) was studied in detail. The morphologic and phenotypic characteristics of this line were distinct from those of alloreactive T lymphocytes. While reacting with a moAb to the sheep red blood cell receptor, it lacked the well-defined pan T cell markers Leu 1 and Leu 4, as well as the markers associated with functional T cell subsets Leu 2a and Leu 3a. Further morphologic, histochemical, and phenotypic characterization revealed this cell line to be strikingly similar to the larger granular lymphocyte (LGL) population, which contains the bulk of the natural killer cell activity normally found in peripheral blood. Cold target blocking studies confirmed the NK specificity of the observed cytotoxicity. Although unlabeled NK targets readily inhibited cytotoxic activity, B-LCL bearing the stimulating antigens of the original MLC failed to inhibit lysis of NK-sensitive targets. The growth of 3.3 was strictly dependent on IL 2 CM. Absorption studies with IL 2-dependent T cells and 3.3 revealed that both of these cell populations were equally effective in removing the growth-promoting factor(s) from IL 2 CM. These data suggest that at least some of MLC-generated NK activity is mediated by a population of cells similar to if not identical to LGL. These cells, in addition, appear to depend on the same growth-promoting factor(s) in IL 2 CM as do classical T lymphocytes.
Development of natural killer cell function in the human fetus.
Authors: Uksila J , Lassila O , Hirvonen T , Toivanen P
Published: December 2022

NK cell activity of four human premature infants between 28 and 33 wk of gestation and eleven human fetuses at 9 to 22 wk of gestation was tested against the K-562 cell line in a 4-hr 51Cr-release assay. Cord blood lymphocytes from premature infants expressed well-developed NK capacity, although the level of cytotoxicity was lower than that of full-term newborns or adults. Cells prepared from fetal liver displayed cytotoxicity against K-562 targets in four out of eleven fetuses, whereas cells from fetal bone marrow, spleen, and thymus expressed only marginal or negative anti-K-562 killing. NK cell activity in the fetal liver was observed as early as at 9 wk of gestation. The functional NK capacity of premature infants and fetuses was augmented in vitro by IFN-alpha treatment. Fetal cells without spontaneous NK activity did not develop cytotoxicity against K-562 target cells in the presence of IFN-alpha. The present results corroborate the concept of the intrauterine development of human NK cell activity.
Identification and partial purification of a B cell growth-promoting material utilizing the BCL1 cell line.
Authors: Thoman M L , Weigle W O
Published: December 2022

A B cell growth-promoting factor (BCGF) can be detected in the culture supernatants of activated murine and human spleen cells, human peripheral blood lymphocytes, and a murine thymoma cell line by the use of the B cell leukemic cell line BCL1, which is induced to proliferate in response to this factor. Although this BCGF stimulates BCL1 cells to proliferate, it is not mitogenic for resting B cells but synergizes with dextran sulphate to induce proliferation of the latter cells. This factor has no T cell-replacing activity in an antibody response. BCGF co-purifies with interleukin 2 (IL 2) by gel chromatography and isoelectric focusing but can be separated by phenyl-Sepharose chromatography.
In vitro immunization to KLH. II. Limiting dilution analysis of antigen-reactive cells in primary and secondary culture.
Authors: Gebel H M , Scott J R , Parvin C A , Rodey G E
Published: December 2022

Limiting dilution analysis was used to estimate the frequency of human peripheral blood T lymphocytes that proliferate in response to in vitro immunization with keyhole limpet hemocyanin (KLH). Antigen-reactive cells (ARC) were estimated 9 days after primary immunization with KLH. The ARC frequency of lymphocytes from 12 subjects ranged from 1:23,800 to 1:52,631. Lymphocytes from five of these subjects were also primed for 12 days with KLH, rechallenged in secondary culture with fresh adherent cells and KLH, and assayed 4 days later. The ARC frequency increased to 1:1,123 to 1:7,247, indicating that T cell clones responsive to KLH had expanded during primary culture. In addition, we observed that the proliferative response of lymphocytes from 5 of the 12 subjects were inhibited at high cell concentrations. Depletion of OKT8+ T cells before culturing with KLH however did not alter the inhibitory effect of high concentrations of T cells.
Evidence for beta 2-microglobulin-like and H-2-like antigenic determinants in Drosophila.
Authors: Shalev A , Pla M , Ginsburger-Vogel T , Echalier G , Lögdberg L , Björck L , Colombani J , Segal S
Published: December 2022

Serologic evidence for the existence of beta 2-microglobulin-, (beta 2m) like and H-2-like antigenic determinants in Drosophila are presented. Drosophila-cultured cells and larvae extract were shown to react specifically with a rabbit anti-rat beta 2m and a rabbit anti-mouse beta 2m antisera. G-200 pooled fractions from Drosophila larvae were shown to react with beta 2m-eluted and glycin-absorbed antisera, but not with beta 2m-absorbed or glycin-eluted antisera. These fractions also quantitatively inhibited the heterologous reaction between the anti-beta 2m antisera and purified human and rat beta 2m. The lack of reactivity of other rabbit antisera or normal serum with Drosophila, as well as the efficiency of absorption of anti-beta 2m reactivity by either rat or KCO% (Drosophila) cells, further supports the presence of beta 2m epitopes on Drosophila cells. Data are also presented showing that certain anti-H-2 alloantisera react with Drosophila. That this reactivity is indeed due to anti-H-2 antibodies is suggested by several lines of evidence, including the removal of cytotoxic alloantibodies and lack of reactivity by other mouse antisera and monoclonal reagents. Preliminary data suggest that the H-2-like and beta 2m-like determinants are physically associated on the cell surface of Drosophila cells. These findings have important implications on current concepts concerning the evolutionary origin and physiologic role of beta 2m and the major histocompatibility complex.
Studies on the cellular nature of Candida albicans-induced suppression.
Authors: Rivas V , Rogers T J
Published: December 2022

Animals treated with formalinized Candida albicans manifest depressed cellular immune activity. Splenocytes from mice treated with as little as 14 micrograms of this material exhibited significantly reduced responses to the T cell-dependent mitogens phytohemagglutinin and concanavalin A. On the other hand, the B lymphocyte-dependent response to bacterial lipopolysaccharide was normal in these cultures. Splenocytes from treated mice were capable of actively suppressing the T cell- (but not B cell-) dependent proliferative response of normal cells. Analysis of splenocytes from Candida-treated mice showed that the suppressor cell is adherent to glass wool, is not adherent to Sephadex G-10, does not phagocytize carbonyl iron, is not susceptible to treatment with anti-Thy-1 plus C, but does bind specifically to anti-immunoglobulin- (anti-Ig) coated dishes. The adherence to the anti-Ig-coated dishes was not due to the simple attachment of Fc receptor-bearing lymphocytes, because dishes coated with the F(ab')2 fragment of rabbit antimouse IgG bound the suppressor cell. These results suggest that the active Candida-induced suppressor cell is composed, at least in part, of surface Ig-bearing B lymphocytes.
Allotype-defined mRNA for rabbit immunoglobulin H and L chains isolated from rabbit-mouse hybridomas.
Authors: Dreher K L , Sogn J A , Gates F T , Kuo M C , Kindt T J
Published: December 2022

Improved procedures have expedited the formation and propagation of stable rabbit-mouse hybridomas (RMH) that secrete rabbit immunoglobulin (Ig) chains and that serve as sources for allotype-defined mRNA, specifying both constant and variable regions of rabbit Ig. The Ig-secreting hybridomas were stabilized by multiple recloning steps and eventually attained a 90% frequency of cells secreting rabbit Ig chains. Stabilized RMH were propagated in vivo in nude (athymic) and in some instances in conventional BALB/c mice. Rabbit Ig products secreted by these RMH cell lines were isolated and were shown to have amino acid sequence characteristics of rabbit Ig chains and that are distinct from those of the mouse. Preparative amounts of polyadenylated RNA-(poly(A) RNA) encoding allotype-defined rabbit Ig chains were isolated from RMH grown as solid tumors. Poly(A) RNA encoding a b4 L chain from one RMH (12F2) and an a3 H chain from another (7D2) were purified 10-fold by sucrose density gradient centrifugation and were characterized in an in vitro translation system. The mRNA encoding the b4 allotype had an S value of 12 and directed the synthesis of a rabbit precursor L chain with m.w. 27,500. Radiochemical amino acid sequence analysis of the L chain precursor has shown it to include a 22 residue leader sequence with a leucine profile similar to that of murine L chain precursors. Analysis of the mRNA encoding the a3 H chain revealed it has an S value of 16 and directed the synthesis of an Ig chain with a m.w. identical to that of the rabbit H chain secreted by the RMH.
Stimulation of secondary anti-MSV cytolytic T lymphocytes with MBL-2 reconstituted membranes.
Authors: Duprez V , Mescher M F , Burakoff S J
Published: December 2022

Membranes and solubilized, reconstituted membranes from Moloney-infected tumors MBL-2 have been used to stimulate in vitro secondary cytolytic T lymphocytes (CTL) in C57BL/6 mice primed and Moloney murine sarcoma virus. Membranes are shown to stimulate the generation of Moloney-specific and H-2 restricted CTL. Stimulation with solubilized, reconstituted membranes required the presence of rat lymphocyte Con A supernatant (containing interleukin 2) during the culture. Reconstituted membranes made in the presence of the detergent-insoluble fraction from the plasma membrane were able to stimulate a response in the absence of Con A supernatant.
The extent of self-MHC restriction of cytotoxic T cells in nude mice varies from mouse to mouse.
Authors: Miller R G , Derry H R , Sarjeant B J
Published: December 2022

There are conflicting results as to whether the response of athymic nude mice to TNP-modified self determinants is or is not H-2 restricted. We cultured spleen cells from 29 individual RNC (H-2k) nude mice with TNP-modified self determinants and tested the cultures for their ability to lyse TNP-modified self (RNC-TNP) and TNP-modified allogeneic (BALB/c-TNP) target cells. Each mouse was stimulated by two different protocols: either by the addition of TNP-modified irradiated nu/+ spleen cells or by TNP modification of the nude responder cells without addition of other cells. All mice could lyse RNC-TNP targets and about one-half could also lyse BALB/c-TNP targets, i.e., there was a 50:50 division between restricted and unrestricted responses. The magnitude of the response against RNC-TNP and whether the response was restricted were both independent of the method of stimulation. We conclude that H-2 restriction in these mice is imposed by an as yet unidentified environmental influence that can vary from one nude mouse to the next. The influence appears to act through negative selection because the modified self response is, if anything, higher in mice showing an unrestricted response.
Role of self carriers in the immune response and tolerance. VIII. Suppression of the MOPC-104E idiotypic response by idiotype-modified self, but not by dextran-modified self.
Authors: Grouix B , Scott D W
Published: December 2022

We have investigated the suppression of the anti-dextran B1355S immune response using our model of modified self. The anti-dextran response is idiotypically well defined in BALB/c mice. This system enables us to examine the contribution of various predominant idiotypes to the antibody response under conditions of suppression by antigen or by idiotype-specific suppressor cells. Our results demonstrate that the total anti-dextran response can be inhibited by pretreatment of animals with dextran-coupled syngeneic spleen cells; however, the representation of major idiotypes constituting this response are not reduced in percentage. In contrast, pretreatment of mice with MOPC-104E-coupled spleen cells leads to a specific suppression of the private IdI-104E idiotype. The total anti-dextran response remains unchanged, as well as proportions of other major idiotypes known (IdI-588 and IdX). This suppression is mediated by Thy-1.2+, Lyt-2.2+ T cells, as demonstrated by adoptive transfer assays. This system will allow the molecular dissection of the regulation of an idiotypically well-defined system for the suppression by either antigen- or idiotype-specific suppressor T cells.
Immune response to the p-azobenzenearsonate (ABA)-GAT conjugate. II. Hapten-specific T cells induced with ABA-GAT in GAT responder X nonresponder F1 hybrids are restricted to the nonresponder haplotype.
Authors: Regnier D , Seman M
Published: December 2022

Immunization of mice with the ABA-GAT conjugate stimulates GAT-specific T helper cells in GAT-responder animals and ABA-specific helpers in nonresponders. Unexpectedly, immunization of (responder X nonresponder) F1 mice, which have the GAT-responder phenotype, leads to the recruitment of both ABA- and GAT-specific clones of T helper lymphocytes. The GAT-reactive population is restricted to the haplotype of the responder parent (Iak), whereas ABA-specific T cells are mostly restricted to the nonresponder one (Ias). This is demonstrated by the ability of monoclonal antibodies to parental la antigens to inhibit T cell proliferation to GAT or ABA-Tyr in vitro. Consistently, ABA-GAT-primed F1 T cells can only activate nonresponder B cells to proliferate in the presence of ABA-Tyr and responder B lymphocytes in the presence of GAT. Furthermore, F1 T cells seem to recognize both ABA and GAT epitopes only in association with molecules encoded by the I-A subregion. Analysis of ABA-specific F1 T cell lines generated by in vitro stimulation with ABA-Tyr or ABA-GAT demonstrates a competition between GAT- and ABA-specific T cells present in the hybrid T cell repertoire and restricted to the same parental I-Ak molecule. The results indicate that F1 macrophages can present both ABA and GAT epitopes to T cells in association with the two parental and hybrid Ia determinants. It seems unlikely that the absence of GAT-specific T cells restricted to the nonresponder I-A in the F1 is due to suppressor T cells. Thus, the competition model that we propose, to explain the selective F1 T cell response to ABA-GAT, leads us to believe that GAT nonresponder animals may lack clones capable of recognizing, with a high affinity, I-As + GAT.