bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibody and immune complexes induce tissue factor production by human endothelial cells.
Authors: Tannenbaum S H , Finko R , Cines D B
Published: December 2022

Patients with systemic lupus erythematosus (SLE) have an increased incidence of arterial and venous thromboses. The mechanism by which thromboses develop in these patients is unknown. We had previously observed that the sera of patients with SLE contain antibodies and immune complexes that can bind to endothelial cells. Because endothelial cells can synthesize tissue factor, a potent activator of coagulation, we studied the effect of IgG complexes and sera from patients with SLE on the production of tissue factor by these cells. Human umbilical venous endothelial cells incubated with heat-aggregated IgG (HA-IgG) (0.5 to 4.0 mg) elaborate procoagulant activity in a dose-dependent manner. All procoagulant activity was found in the particulate cell fraction, and none was secreted into the medium. Maximum expression of procoagulant activity required 6 to 8 hr, and its production was totally inhibited by the addition of cyclohexamide or actinomycin D. The presence of gel-filtered platelets augmented production of procoagulant activity by endothelial cells stimulated by HA-IgG. Endothelial cell procoagulant activity was not inactivated by diisofluoropropylphosphate, required the presence of Factor VII for its expression, and was neutralized by a specific anti-tissue factor antibody. Endothelial cells incubated with sera from 14 of 16 patients with SLE produced increased amounts of tissue factor compared with 21 normal sera (p less than 0.025). Fractions of two SLE sera containing monomeric IgG, IgA, or IgM, as well as fractions containing IgG complexes, each stimulated endothelial cells to produce more tissue factor than similar fractions prepared from two normal sera. These studies demonstrate that endothelial cells will produce the procoagulant tissue factor after exposure to anti-endothelial cell antibodies or IgG-containing immune complexes. The production of tissue factor by endothelial cells at sites of immune vascular injury may play a role in the development of thromboses in patients with SLE.
Corticosteroids enhance the binding of recombinant interferon-gamma to cultured human monocytes.
Authors: Strickland R W , Wahl L M , Finbloom D S
Published: December 2022

Human peripheral blood monocytes possess receptors on their surface for human interferon-gamma (IFN-gamma). Inasmuch as the biologic effects of IFN-gamma are thought to be mediated through binding of the molecule to this receptor, modulation of receptor number may be a means for enhancing the effect of IFN-gamma. We examined this possibility by treating human monocytes in culture with dexamethasone. At a dexamethasone concentration of 200 nM, there was a twofold increase in the number of 125I-recombinant IFN-gamma molecules bound to the cell. An effect was noted at concentrations of dexamethasone greater than 50 nM, and was observed as early as after 18 hr of treatment. The observed effect was the result of both a 50% decrease in receptor number in untreated cells and an increase to pretreatment levels or greater in cells incubated with dexamethasone. These results suggest that dexamethasone may modulate the effects of IFN-gamma on monocytes by changes in receptor number.
A monoclonal anti-mouse LFA-1 alpha antibody mimics the biological effects of B cell stimulatory factor-1 (BSF-1).
Authors: Mishra G C , Berton M T , Oliver K G , Krammer P H , Uhr J W , Vitetta E S
Published: December 2022

This study describes the generation of a monoclonal mouse x rat antibody (G-48) that recognizes a determinant on the serologically defined LFA-1 alpha-chain. It immunoprecipitates two noncovalently associated polypeptides of 176,000 and 95,000 Mr respectively from lysates of radioiodinated BCL1 cells, T cells, and B cells. G-48 mimics the biological actions of BSF-1 by inducing increased levels of Ia antigen expression on resting B cells, augmenting the proliferation of anti-delta-stimulated B cells, and in insolubilized form, inducing IgG1 secretion by LPS-activated B cells. G-48 does not have BCDF mu, BCGF II, nor IL 2 activity. These results demonstrate that LFA-1 plays an important role in B cell activation, proliferation, and differentiation.
Molecular analysis of an HLA-A2 functional variant CLA defined by cytolytic T lymphocytes.
Authors: Ezquerra A , Doménech N , van der Poel J , Strominger J L , Vega M A , López de Castro J A
Published: December 2022

By using cytolytic T lymphocytes (CTL), the HLA-A2 serologic specificity may be divided into at least four subtypes designated as A2.1 to A2.4. The HLA-A2.4 antigen expressed by donor CLA is not recognized by allogeneic CTL specific for either A2.1, A2.2, or A2.3, but is indistinguishable from HLA-A2.1 by H-Y-specific, HLA-A2-restricted CTL and by isoelectric focusing. The structure of this HLA-A2.4 antigen was compared with the known structure of the main A2.1 subtype expressed on JY cells to establish the molecular basis for the immunologic differences between the two antigens. Comparative peptide mapping and radiochemical sequence analysis were used to establish that they differed by a single amino acid change: Phe at position 9 in HLA-A2.1 was replaced by Tyr in HLA-A2.4 from donor CLA. This position displays the highest variability score among all polymorphic residues of the class I HLA antigens. But its participation in the specific determinants recognized by CTL has not been previously established, because no other known HLA variant or H-2 mutant has been found to vary at this position. In addition, HLA-A2.4 from CLA is the only HLA-A2 subtype antigen that is identical to A2.1 in the segment spanning residues 147 to 157, a region in which all three A2.1, A2.2, and A2.3 antigens are different.
T cell specificity in twice-irradiated F1----parent bone marrow chimeras: failure to detect a role for immigrant marrow-derived cells in imprinting intrathymic H-2 restriction.
Authors: Ron Y , Lo D , Sprent J
Published: December 2022

In an attempt to resolve the issue of whether H-2-restricted T cell specificity is controlled by thymic epithelial cells or by cells of the macrophage/dendritic cell (M phi/DC) lineages, long-term F1----parent chimeras were subjected to secondary irradiation and reconstitution with F1 marrow cells. The rationale was that if F1 M phi/DC enter the thymus only quite slowly after irradiation, as claimed by other investigators, leaving F1----parent chimeras for a period of several months before re-irradiation would ensure that the new wave of T cells generated in the thymus of the chimeras would have no difficulty in making contact with donor-derived F1 M phi/DC. According to the view that M phi/DC rather than epithelial cells control H-2 restriction, the T cells differentiating in these chimeras would be expected to show H-2 restriction to both parental strains. In practice, T cells from twice-irradiated (1000 + 800 rad) chimeras showed strong restriction to host (thymic) H-2 determinants, the degree of restriction to host determinants being as marked as with T cells from once-irradiated chimeras. This finding applied both to T proliferative responses to KLH assayed in vitro and to T helper function for sheep erythrocytes measured in vivo. Preliminary experiments established that the initial dose of irradiation used for preparing the chimeras (1000 rad) resulted in almost total replacement of intrathymic M phi/DC by donor-derived cells within 4 wk of irradiation; M phi/DC were typed by determining their capacity to stimulate mixed-lymphocyte reactions. Collectively, the data imply that, at least under the conditions used, H-2-restricted T cell specificity is controlled by epithelial cells rather than by M phi/DC.
Immunoglobulin-dependent helper T cells: studies in the MOPC-315 system suggest a novel surface antigen phenotype.
Authors: Rohrer J W , Kemp J D
Published: December 2022

We have previously provided evidence that the SRBC-immune helper T (TH) cells which enhance MOPC-315 plasmacytoma cell secretory differentiation in vivo (THd cells) differ in specificity, accessory cell requirements, and Qa-1 expression from the SRBC-immune TH cells which enhance MOPC-315 cell growth in vivo (THg cells). Indeed, like other immunoglobulin-dependent TH cells, THd cells in the 315 system do not develop in anti-IgM-treated, B cell-deficient mice, whereas THg cell development is unaffected. In this report, we provide evidence for other differences in the expression of surface antigens by these two TH cell populations. We find that, like most Lyt-1+, 2- T cells, the THg cells can be eliminated by monoclonal anti-L3T4 antibody and complement treatment, whereas such treatment had no effect on adoptive transfer of SRBC-immune THd cell activity. Similarly, THg cell activity was eliminated from SRBC-immune T cells by treatment with monoclonal anti-T cell receptor beta-chain allotope antibody plus anti-rat IgG and complement, whereas THd cell activity remained intact. Both helper cell activities were deleted by either anti-Lyt-1.2 or anti-Thy-1.2 antibody and complement treatment. Interestingly, the THd cell activity was abrogated by treating SRBC-immune T cells with monoclonal anti-B220 or monoclonal anti-p50 antibodies (RA3-3A1/6.1 and RA3-2C2/1, respectively) and complement, whereas THg cell activity was unaffected. Additional controls indicated that the THd effects did not arise by virtue of a two-cell interaction between a Thy-1+, B220- cell and a Thy-1-, B220+ cell, and it is therefore proposed that the THd effect arises from a single population of cells that exhibit a unique phenotype (Thy-1+, Ly-1+, 2-, L3T4-, B220+). The proposal is further supported by studies conducted with a T cell clone which promotes MOPC-315 cell secretory differentiation in vitro and which exhibits this surface antigen phenotype. The serologic differences between these two TH cell populations stress even further the likelihood that B cell growth and differentiation enhancement are mediated by distinct T cell subsets in this system, and raise the possibility that immunoglobulin-dependent TH cells in other systems will routinely exhibit a unique surface antigen profile. These data also imply that immunoglobulin-dependent TH cells (such as the THd cells) may not express antigen receptors that are identical to those expressed by MHC-restricted helper cells (such as our THg cells).
Identification and characterization of mitochondria autoantigens in progressive systemic sclerosis: identity with the 72,000 dalton autoantigen in primary biliary cirrhosis.
Authors: Alderuccio F , Toh B H , Barnett A J , Pedersen J S
Published: December 2022

Sera from eight out of 62 (14.5%) patients with progressive systemic sclerosis (PSS) reacted by immunoblotting with a 72,000 dalton antigen and one, a patient with concomitant primary biliary cirrhosis (PBC), reacted with the 72,000 dalton and a 47,000 dalton antigen. Reactivity with these antigens was not seen with any of 111 control sera. The antigens with minor variations in m.w. were present in a variety of cultured cells and tissue homogenates from different species. Subcellular fractionation studies localized the antigens to the mitochondria. Of 19 sera from patients with other diseases selected for immunofluorescence staining for anti-mitochondria autoantibody, nine reacted with the 72,000 dalton antigen, seven reacted with both the 72,000 and 47,000 dalton antigens, and three reacted with the 47,000 dalton antigen. These results show that serum reactivity with the 72,000 dalton and 47,000 dalton mitochondria autoantigens is found with some patients with PSS. Because mitochondria autoantibodies that are reactive with the 72,000 dalton and 47,000 dalton polypeptides are also found in patients with PBC, the present finding provides additional support for the association of PSS with PBC. Prior absorption of rat liver homogenate with PBC sera removed PSS serum reactivity with a 63,000 dalton antigen, the equivalent 72,000 dalton antigen in rodents, and vice versa, showing that both PBC and PSS sera recognize the same antigen.
Lipopolysaccharide modulates receptors for leukotriene B4, C5a, and formyl-methionyl-leucyl-phenylalanine on rabbit polymorphonuclear leukocytes.
Authors: Goldman D W , Enkel H , Gifford L A , Chenoweth D E , Rosenbaum J T
Published: December 2022

Peripheral blood polymorphonuclear leukocytes (PMNL) isolated from rabbits after an i.v. injection of endotoxin exhibited decreased chemotactic migration in response to leukotriene B4 (LTB4) and C5a, but not N-formyl-methionyl-leucyl-phenylalanine (fMLP), after endotoxin treatment. The binding of radiolabeled LTB4, fMLP, and C5a to isolated PMNL was assessed in order to determine whether altered receptor expression could account for the observed functional changes. Control PMNL expressed binding sites for fMLP, LTB4, and C5a similar to those previously characterized from human PMNL. Control PMNL expressed a single class of 14,600 +/- 2700 receptors for fMLP with a mean dissociation constant (Kd) of 2.0 +/- 0.6 nM at 0 degrees C, whereas two subclasses of binding sites were expressed for LTB4: 10,300 +/- 6800 high-affinity and 85,600 +/- 53,000 low-affinity binding sites per PMNL with mean Kd for LTB4 of 0.75 +/- 0.43 nM and 70 +/- 58 nM (mean +/- SD, n = 5), respectively. Control PMNL bound [125I]-C5a in a dose-dependent and saturable manner at 24 degrees C. At saturating concentrations of C5a, PMNL obtained from control rabbits bound 270,000 +/- 50,000 molecules of [125I]-C5a with half-maximal binding occurring at [125I]-C5a concentrations of 5.5 +/- 1.9 nM. The binding of LTB4 and C5a to PMNL obtained 24 hr after an i.v. injection of endotoxin was markedly decreased compared with control PMNL. PMNL from endotoxin-treated rabbits exhibited 68% fewer high-affinity binding sites per PMNL for LTB4 and a 51% decrease in the amount of [125I]-C5a bound at saturating concentrations compared with control PMNL. There was no significant change in the Kd of the high-affinity binding sites for LTB4, no change in the Kd and number of the low-affinity binding sites for LTB4, and a small decrease in the apparent Kd for C5a to 3.3 +/- 1.1 nM. Even though the pretreatment with i.v. endotoxin did not alter chemotactic or degranulation responses elicited by fMLP, the endotoxin pretreatment induced an eightfold increase in the receptor density without altering the Kd for fMLP. Decreased receptor expression could account in large part for the decreased chemotactic responsiveness towards C5a and LTB4 induced by LPS. The finding that a substantial increase in receptors for fMLP need not be accompanied by a comparable functional change suggests that decreased efficiency in receptor coupling to intracellular biochemical events may also result from i.v. endotoxin.
Expression and function of asialo GM1 in alloreactive cytotoxic T lymphocytes.
Authors: Ting C C , Bluestone J A , Hargrove M E , Loh N N
Published: December 2022

In the present study we examined asialo GM1 (AsGM1) expression and its function in alloreactive cytotoxic T lymphocytes (CTL). We consistently found that the cytotoxic activity of bulk culture-derived allo-CTL was susceptible to the treatment of anti-AsGM1 (alpha AsGM1) plus complement. To further determine whether the expression of AsGM1 was maintained in CTL, we examined cloned T cells. The expression of AsGM1 in the T cell clones was assessed by their susceptibility to lysis by alpha AsGM1 plus complement and the reduction or abrogation of their cytotoxic activity by this treatment. It was found that, with one exception, all Lyt-2+, Thy-1+ CTL clones were AsGM1+ (seven out of eight), independent of their class specificity (class I or class II). In contrast, all Thy-1+, L3T4+ CTL (2) or helper T cell (4) clones AsGM1-. These findings suggested that there was a close association between the expression of AsGM1 and the expression of Lyt-2. The cytotoxic reaction of the anti-class I MHC CTL clones that expressed AsGM1 was blocked by alpha AsGM1 or alpha Lyt-2 antibody. The Lyt-2+, AsGM1+ anti-class II MHC CTL clone-mediated lysis was inhibited by alpha AsGM1. Addition of AsGM1 in micelle form (AsGM1-M) alone also blocked the cytotoxic reactions. Addition of other structurally similar but antigenically different glycolipids or other non-AsGM1-containing liposome preparations did not affect CTL-mediated cytotoxicity. Furthermore, adding both alpha AsGM1 and AsGM1-M together at proper doses inhibited the blocking effect (deblocking) of either alone, and other structurally similar glycolipids did not inhibit the blocking. The deblocking was specific, since AsGM1-M did not affect the blocking by alpha Lyt-2. These findings indicate that not only is AsGM1 expressed in a majority of Lyt-2+ CTL clones, but it may also be involved in the CTL- target interaction to mediate lytic reaction.
Expression of MEL-14 antigen is not an absolute requirement for dissemination to lymph nodes after adoptive transfer of murine T lymphocyte clones.
Authors: Bookman M A , Groves E S , Matis L A
Published: December 2022

The inability of established antigen-specific murine T lymphocyte clones to recirculate well in vivo has been attributed to loss of the surface glycoprotein gp90MEL-14, which is important for specific adherence to post-capillary high endothelial venules in peripheral lymph nodes (LN). Defective recirculation of clones may contribute to inefficient adoptive immunotherapy when compared with fresh immune spleen or LN populations. To optimize models of adoptive immunotherapy, we sought to improve recirculation of Thy-1.2+, L3T4+ clones by inducing reexpression of MEL-14 antigen (gp90MEL-14). Clones were analyzed after treatment with differentiating agents, incubation in the presence or absence of recombinant interleukin 2 (rIL 2), coincubation in vitro with nonirradiated Thy-1.1 LN or thymus cells, or adoptive transfer into Thy-1.1 hosts. We were unable to demonstrate induction of gp90MEL-14 in any case. However, although clones remained MEL-14 negative, they were able to disseminate widely after subcutaneous adoptive transfer in the presence of clone-specific antigen and rIL 2 into Thy-1.1 mice pretreated with cyclophosphamide. Withdrawal of exogenous rIL 2 was associated with rapid disappearance of clones from all sites. We conclude that murine T cell clones undergo a step in terminal differentiation that precludes surface expression of gp90MEL-14 and that these clones would be unlikely to provide a source of long-lived recirculating memory T lymphocytes. However, under appropriate circumstances it is possible for antigen-specific clones to disseminate widely among host LN and mediate short-term immune responses.
In vivo thymocyte maturation. BUdR labeling of cycling thymocytes and phenotypic analysis of their progeny support the single lineage model.
Authors: Penit C
Published: December 2022

Spontaneously cycling thymocytes have been labeled in vitro and in vivo by bromodeoxyuridine (BUdR), a non-reutilized precursor of DNA that is detectable by a monoclonal antibody. Studies of BUdR-labeled cells have included the determination of their anatomical location, size, and nuclear aspects and of their cell surface phenotype. Dividing blasts were initially located in the cortex (mainly but not exclusively in the subcapsular region) and expressed the double-negative (Lyt-2- L3T4-) and double-positive (Lyt-2+ L3T4+) phenotypes. The fate of these cells have been determined in days after BUdR administration, and we observed an initial double-negative to double-positive transition that was followed by the death of the majority of labeled cells in the cortex. As of day 3, the few surviving cells acquired a mature helper phenotype (Lyt-2- L3T4+) and began migrating into the thymic medulla. The exclusive medullary location of blast cell progeny was observed between days 5 and 10 post-BUdR administration. These results suggest a direct precursor-product relationship between dividing cortical cells and mature medullary thymocytes, and therefore support the single lineage model of intrathymic differentiation.
Anti-interleukin 2 receptor antibody suppresses delayed-type hypersensitivity to foreign and syngeneic antigens.
Authors: Kelley V E , Naor D , Tarcic N , Gaulton G N , Strom T B
Published: December 2022

Delayed-type hypersensitivity (DTH) requires stimulation of antigen-specific helper T cells (Th). Because de novo expression of the interleukin 2 receptor (IL 2R) is a necessary step in T cell activation, we tested the capacity of anti-mouse IL 2R monoclonal antibody (Mab) and anti-Th Mab (anti-L3T4) to block DTH. We examined the effect of these Mab on two distinct DTH systems, i.e., to foreign hapten (trinitrobenzenesulfonic acid) and to this hapten present on syngeneic blasts. Both anti-IL 2R and anti-L3T4 Mab suppress DTH. Therapy is as effective treating with one injection just before challenge with the hapten as giving six daily injections. These data indicate that DTH is dependent on a discrete subset of activated IL 2R-positive T cells, because anti-IL 2R therapy, which targets few cells, is as effective as anti-L3T4 Mab treatment, which targets the entire Th subset.
Inhibition of interleukin 1 activity by a factor in submandibular glands of rats.
Authors: Kemp A , Mellow L , Sabbadini E
Published: December 2022

With the sequential use of ammonium sulfate precipitation, gel filtration and chromatofocusing, we have partially purified from extracts of the submandibular glands of rats a factor (referred to as submandibular gland's immunosuppressive factor or SMG-ISF) capable of inhibiting the in vitro proliferation of mitogen- and antigen-stimulated murine lymphocytes. The semi-purified suppressor fractions had an isoelectric point of 4.4 to 4.5 and consisted of at least three molecular species. These active fractions suppressed the mitogenic effects of Concanavalin A phytohemagglutinin, and lipopolysaccharide. In vitro immune reactions such as the mixed lymphocyte culture MLC reaction and the production of cytotoxic T lymphocytes (CTL) across major histocompatibility barriers in mice were also suppressed. These in vitro immunosuppressive effects required the addition of the suppressor fractions early after the initiation of the cultures and were reversed if the factor was removed from the cultures at least 48 to 72 hr before the completion of the assays. The active fractions did not affect the proliferation of CTLL 2 cells induced by interleukin 2 (IL 2), but inhibited the mitogenic and co-stimulatory effects of IL 1 on mouse thymocytes, and in this effect showed a dose-response relation suggestive of a competitive mechanism. These characteristics of SMG-ISF indicate a specific inhibition of the activity of IL 1.
Cross-linking of insulin receptors to MHC antigens in human B lymphocytes: evidence for selective molecular interactions.
Authors: Samson M , Cousin J L , Fehlmann M
Published: December 2022

Molecular interactions between insulin receptors and MHC antigens were investigated in human B cells. Two B lymphoblastoid cell lines, IM-9 and 526, chosen for their high insulin binding capacity, were found to express 15,000 and 25,000 insulin receptors per cell, respectively. Insulin receptors were labeled with a 125I-photoreactive insulin analogue, and all other surface proteins by lactoperoxidase-catalyzed radioiodination. Neighbor proteins were cross-linked with a cleavable homobifunctional reagent dithio-bis-(succinimidyl propionate) (DSP) and solubilized before immunoprecipitation by anti-HLA monoclonal antibodies. Gel analysis of the precipitated proteins showed that 90% of insulin receptors precipitable by anti-insulin receptor antibodies were precipitated by anti-class I antibodies (anti-heavy chain and anti-beta 2-microglobulin) after cross-linking with 2 mM DSP. In neither IM-9- nor 526 cells could HLA antigens be precipitated by anti-insulin receptor antibodies, suggesting that the concentration of class I antigens largely exceeds the concentration of insulin receptors at the cell surface. In 526 lymphocytes, class I MHC antigens were also found to adjoin class II antigens, since both molecules could be coprecipitated with anti-HLA A, B, C and with anti-HLA-DR antibodies after chemical cross-linking. Down-regulation of insulin receptors by chronic exposure of IM-9 cells to insulin did not affect the amount of MHC molecules present on the cell surface, and conversely, class I MHC molecules were internalized in 526 cells irrespective of the presence of insulin. These results thus show that insulin receptors and MHC antigens form multimolecular complexes in the plasma membrane of cultured human B cells. These interactions, which do not appear to influence the regulation of these proteins on the cell surface, may be involved in the mechanism of hormone signaling.
The interaction of monomeric and complexed mouse monoclonal IgG with rat basophilic leukemia cells: a subset of IgG molecules can bind to RBL cell Fc receptors for IgG.
Authors: Hall T J , Rittenberg M B
Published: December 2022

Rat basophilic leukemia (RBL) cells were shown to bind mouse monoclonal (MC) IgE and certain mouse monomeric IgG1 and IgG2b monoclonal antibodies (MAb) by using a haptenated sheep red blood cell (SRBC) rosetting assay. Rosette formation was antibody concentration dependent with all three immunoglobulin isotypes, but at least 100 times more IgG than IgE was required to form a similar number of rosettes. It was shown by FACS analysis and rosette formation that a subset (8/23) of the IgG MC was able to bind to RBL cells as monomers. However, the majority 15/23 did not bind or bound weakly (less than 25% rosettes) unless in the form of antigen-antibody complexes. As complexes, all IgG subclasses except IgG3 could produce rosettes with RBL cells. None of the IgM or IgA MC tested formed rosettes, even in complexed form. By inhibition studies it is demonstrated that mouse IgG1, IgG2a, and IgG2b MC bind to the same Fc receptor. Mouse IgE was only partially able to inhibit IgG-dependent rosettes at high concentrations, and none of the IgG MC were able to inhibit IgE-dependent rosettes. These results suggest that the interaction of mouse IgG is quite specific for the RBL cell FcG receptor. Because deaggregated polyclonal mouse IgG was a weak inhibitor of MC IgG sensitization of RBL cells, the results are discussed in terms of the heterogeneity and possible abnormality of some MAb.
L3T4+ T lymphocytes play a major role in the pathogenesis of murine cerebral malaria.
Authors: Grau G E , Piguet P F , Engers H D , Louis J A , Vassalli P , Lambert P H
Published: December 2022

The pathogenic importance of L3T4+ T cells in the development of murine cerebral malaria was demonstrated by the following observations. First, in vivo administration of an anti-L3T4 monoclonal antibody protected Plasmodium berghei-infected CBA mice from the development of neurologic symptoms and acute death. In contrast, injection with an MAb directed against the Ly.2+ T cell subset had no protective effect. Second, thymectomized, irradiated, and bone marrow reconstituted (ATxBM) CBA mice did not develop acute cerebral malaria when infected by P. berghei, although parasitemia and anemia rose to the same extent as in normal P. berghei-infected CBA mice. The occurrence of lethal neurologic perturbations could be restored in ATxBM mice selectively reconstituted with L3T4+ Ly.2-lymphocytes but not with Ly.2+ L3T4- cells. Third, adoptive transfer of L3T4+ cells from mice dying of cerebral malaria into euthymic mice subsequently infected by P. berghei led to an acceleration of the disease. These results confirm that cerebral malaria in mice is the expression of immunopathologic reactions and outline the particular pathogenic importance of L3T4+ T cells.
Effect of age on the capacity of the bone marrow and the spleen cells to generate B lymphocytes.
Authors: Francus T , Chen Y W , Staiano-Coico L , Hefton J M
Published: December 2022

The effect of age on the regeneration of the B cell population was studied by cell transfer methods, using the allotype-congenic mouse strains BALB/c (Igha) and C.B-17 (Ighb) as donors of old and young bone marrow (BM) and spleen cells, and C.AL-20 (Igho) as recipients. This design allowed us to identify the origin of the sIgD+ B cells present in the recipients. It was found that in a simple cell transfer, BM cells or spleen cells of aged donors could reconstitute the peripheral B cell population of irradiated, thymectomized recipients essentially as effectively as could BM or spleen cells from young donors. However, when BM cells from aged donors and from young donors were mixed and were used to reconstitute a single recipient, the cells from the aged donor were less efficient than were the cells from the young donor. We found that sIgD+ B cells of young donor origin predominated in the peripheral B cell population of the recipient at 3 to 6 wk after cell transfer. In the BM of the recipients, however, there was no difference in the incidence of sIgD+ B cells derived from the young and the old donors. When recipients were reconstituted with a mixture of spleen cells from old and young mice, the sIgD+ cells of young donor allotype showed a tendency to predominate in the peripheral B cell population, although this predominance was not statistically significant. Under such competitive conditions, the spleen cells of aged donors were less efficient than the BM of aged donors in reconstituting the sIgD+ B cell population of the recipient's BM, but were more efficient in reconstituting the splenic sIgD+ cells. Thus, a subtle defect in the B cell precursor population of the BM and the spleen of aged mice has been demonstrated. The role of T cells in the generation of sIgD+ cells was also analyzed.
Ecto-5'-nucleotidase expression during human B cell development. An explanation for the heterogeneity in B lymphocyte ecto-5'-nucleotidase activity in patients with hypogammaglobulinemia.
Authors: Thompson L F , Ruedi J M , O'Connor R D , Bastian J F
Published: December 2022

Ecto-5'-nucleotidase (ecto-5'-NT) activity was measured in human B cells at different stages of development. Ecto-5'-NT activity of B cell preparations from fetal spleen and cord blood was 5.08 and 5.59 +/- 2.8 nmol/hr/10(6) cells, respectively; that of B cell preparations from adult peripheral blood, spleen, or lymph node was fivefold to sixfold higher (27.9 +/- 12, 29.2 and 33.8 nmol/hr/10(6) cells, respectively). The increased enzyme activity in B cell preparations from adult peripheral blood as compared with cord blood paralleled increased percentages of 5'-NT+ cells (69 +/- 12% vs 32 +/- 17%) and an average of twice as much enzyme activity per positive cell. Small, resting B cells that cannot synthesize Ig in vitro in response to pokeweed mitogen (PWM) were isolated from adult peripheral blood by mouse erythrocyte rosetting. Total ecto-5'-NT activity and the percentage of 5'-NT+ cells were equivalent in total B cells and the mouse erythrocyte rosette-positive subpopulation. Thus, ecto-5'-NT activity is acquired before B cells gain the ability to differentiate into Ig-secreting plasma cells in response to PWM. Ecto-5'-NT activity was also measured in B cell preparations from eight patients with common variable immunodeficiency. Six had reduced ecto-5'-NT activity (2.83 to 15.4 nmol/hr/10(6) cells), and two had normal activity (34.7 and 58.2 nmol/hr/10(6) cells). B cells from all six patients with low ecto-5'-NT activity failed to synthesize Ig when cultured with PWM and normal irradiated T cells. Of the two patients with normal B cell ecto-5'-NT activity, one also had B cells unresponsive to PWM, but B cells from the other patient appeared to more normal, in that they synthesized IgM and IgG when cultured with PWM plus irradiated allogeneic T cells. Thus, measurement of B cell ecto-5'-NT activity allows the subclassification of patients who have a common inability to synthesize immunoglobulin in vitro response to PWM. B cells with low ecto-5'-NT activity are presumably blocked at an earlier stage in development than B cells with normal ecto-5'-NT activity. Evaluation of ecto-5'-NT activity along with the expression of other B cell surface antigens should aid in the definition of discrete stages of B cell development.
IgG subclasses of anti-tetanus toxoid antibodies in adult and newborn normal subjects and in patients with systemic lupus erythematosus, Sjogren's syndrome, and drug-induced autoimmunity.
Authors: Rubin R L , Tang F L , Lucas A H , Spiegelberg H L , Tan E M
Published: December 2022

The IgG subclasses of anti-tetanus toxoid (anti-TT) antibodies were quantitated in normal sera and sera from patients with rheumatic disease. Detection relied on a set of four mouse monoclonal antibodies, each of which showed specificity for the respective isotype, independent of gamma-chain allotype or light chain class of the human antibody. Approximately 90% of the total anti-TT activity in normal adults and patients with Sjogren's syndrome was IgG1. In addition, IgG4 antibodies were detected in one-half the samples, but IgG2 and IgG3 antibodies were observed in only two out of 36 sera. However, antibodies elicited in children immunized with TT were exclusively IgG1 and IgG3, with IgG4 antibodies detectable only at birth (presumably due to transplacental passage of antibody) in three of 12 children. In contrast to normal adults, patients with systemic lupus erythematosus (SLE) and drug-induced autoimmunity (DIA) had a more promiscuous isotype profile. IgG2 and/or IgG3 anti-TT antibodies were detected in 13 of 22 SLE patients and IgG3 antibodies in six of 11 patients with DIA. IgG4 anti-TT antibodies were predominant in seven of these 33 patients. These findings suggest that IgG isotypes may depend on the frequency of the stimulus, but global alterations in immunologic status as reflected in systemic autoimmune disease may override the homeostatic mechanisms that control isotype restriction.
IgG subclasses of autoantibodies in systemic lupus erythematosus, Sjogren's syndrome, and drug-induced autoimmunity.
Authors: Rubin R L , Tang F L , Chan E K , Pollard K M , Tsay G , Tan E M
Published: December 2022

The IgG subclasses displayed by autoantibodies were examined in patients with systemic rheumatic diseases. Solid-phase assays performed with purified antigens were combined with a set of four mouse monoclonal antibodies specific for each human subclass to provide quantitative data for all the major autoantibody specificities. IgG1 accounted for an average of 55% of the total antibody activity to native and denatured DNA, Sm antigen, and histone and constituted significantly more anti-SS-B and anti-nRNP (84% and 92%, respectively). The remaining antibody activity consisted largely of IgG3, and this subclass was particularly prominent with anti-histone and anti-Sm in patients with systemic lupus erythematosus. In contrast, IgG2 constituted 3 to 12% of the anti-native and anti-denatured DNA and less than 5% of the anti-SS-B/La activity in only three patients with Sjogren's syndrome. IgG2 was essentially undetectable in antibodies to Sm and RNP antigens. IgG4 was also uncommon, although this isotype was significantly more prevalent in anti-histone from patients treated with procainamide showed that the isotype distribution of anti-histone and anti-denatured DNA remained remarkably constant. However, during periods of large increases in autoantibody activity, a shift from predominantly IgG3 to predominantly IgG1 occurred, consistent with the interpretation that there might be a sequential activation of heavy chain constant regions as the immune response matures. The disproportionately high levels of IgG1 and IgG3 displayed by all the autoantibody specificities examined may indicate that a common immunogenic feature of autoantigens or a common control mechanism underlies the regulation of autoantibody expression.
Natural killer-sensitive targets stimulate production of TNF-alpha but not TNF-beta (lymphotoxin) by highly purified human peripheral blood large granular lymphocytes.
Authors: Peters P M , Ortaldo J R , Shalaby M R , Svedersky L P , Nedwin G E , Bringman T S , Hass P E , Aggarwal B B , Herberman R B , Goeddel D V
Published: December 2022

Highly purified populations of large granular lymphocytes (LGL) have been shown to mediate natural killer (NK) cell activity. The mechanism of target cell killing by NK cells is as yet undefined; however, it has been postulated that such killing may involve soluble cytotoxic factors produced and secreted by NK cells. The data presented show that NK-sensitive, but not NK-resistant, tumor cell lines induce highly purified populations of human LGL to produce factors with cytotoxic and/or cytostatic activities. We have identified one of these factors as tumor necrosis factor-alpha (TNF-alpha), and have shown that production of this factor is enhanced by recombinant human interferon-gamma (rHuIFN-gamma). We have also examined the role of TNF-alpha in the cytotoxic function of NK cells. The data show that although highly purified LGL populations produce low levels of TNF-alpha, the cytotoxic/cytostatic activity of this lymphokine on tumor target cells does not correlate with the cytotoxic activity of highly purified populations of LGL on tumor target cells. Furthermore, NK cell-mediated cytotoxicity is not reliably inhibited by antibodies directed against various epitopes of recombinant human TNF-alpha and/or recombinant TNF-beta (lymphotoxin) or rHuIFN-gamma. These data show that although TNF-alpha is produced by highly purified NK-containing LGL cell populations, this factor does not appear to be responsible for NK cell cytotoxicity against classical NK target cells such as Molt-4 or K562. We suggest that NK function can be attributed to a combination of factors rather than to a single factor alone, and that at least two major phenomena are involved in LGL function: the rapid cytotoxic events which lead to the cell lysis measured in classical in vitro NK assays such as against K562; and the release of factors such as TNF-alpha with cytotoxic/cytostatic activities which would inhibit the growth of invading tumor cells in vivo.
FcR epsilon+ lymphocytes and regulation of the IgE antibody system. V. Preliminary physicochemical characterization of the T cell-selective IgE-induced regulant EIRT.
Authors: Marcelletti J F , Katz D H
Published: December 2022

We previously showed that murine lymphoid cells exposed to elevated levels of IgE exhibit the de novo expression of Fc receptors for IgE (FcR epsilon), and the production of soluble mediators, which we have termed IgE-induced regulants (EIR). Described herein is the preliminary physicochemical characterization of one such regulant, that being the EIR responsible for the Lyt-2+ T cell-dependent expression of FcR epsilon and secretion of an IgE-binding factor (IgE-BF) which can potentiate IgE synthesis; the former activity has been denoted EIRT for its selectivity of action on T cells, and the latter activity has been termed enhancing effector molecule (EEM) for its presumed potentiating influence on IgE antibody synthesis. Characterized in parallel was the conventional lymphoid cell-derived cEIRT and a murine monoclonal T cell hybridoma-(MBI-2)-derived mcEIRT. EIRT from either source was shown to exhibit the characteristics of a protein with a molecular mass of 45 to 60 kd. Once enriched by gel filtration, neither cEIRT nor mcEIRT preparations displayed any other EIR-like activity except that of EIRT, as evidenced by the ability of these preparations to act selectively to induce the Lyt-2 T cell-dependent expression of FcR epsilon and the production of EEM, the lack of detectable SFA activity that could induce Lyt-1+ T cells to produce the IgE-BF denoted suppressive effector molecule (SEM), and the lack of detectable levels of the B cell-selective EIRB, as indicated by the incapacity of either preparation to induce B cell FcR epsilon expression. Neither cEIRT nor mcEIRT displayed IgE-binding affinity, in contrast to the EEM produced in response to stimulation with these regulants. The only EIR-like activity detected in the unfractionated supernatant fluid from cultures of the monoclonal T cell hybridoma MBI-2 was that of EIRT. Careful in vitro analysis established that such preparations did not contain enhancing factor of allergy (EFA), SFA, EIRB, or IgE-BF. Thus, the enhancement of IgE synthesis observed in animals given this mcEIRT preparation was most likely due to the activity of EIRT known to be present. During the course of these studies, clues as to the physicochemical nature of other EIR activities was obtained. Thus, upon molecular sieve analysis, two distinct molecular mass species of EIRB (one 15 to 20 kd and the other 30 to 35 kd) were demonstrated to be present in conventional lymphocyte-derived cEIR.(ABSTRACT TRUNCATED AT 400 WORDS)
Characterization of two distinct DR beta chain alleles at the beta III locus of the DR5 haplotype: beta III alleles are highly conserved.
Authors: Didier D K , Schiffenbauer J , Shuman S , Abruzzini L F , Gorski J , Watling D L , Tieber V L , Schwartz B D
Published: December 2022

The HLA-DR beta region of at least two members of the DRw52 (MT2) supertypic group (DR3, DR5, DRw6, and DRw8) has recently been shown to contain three beta-chain genes--beta I, beta II, and beta III, ordered in the direction of transcription. beta III is apparently a duplication of beta I. Both beta I and beta III are expressed, whereas beta II is a pseudogene. We previously reported the sequence of the DR5 beta I cDNA from the homozygous DR5 cell line Swei. We report here the sequence of two different DR5 beta III cDNA from the same cell line. The assignment of the genes of this and other members of the DRw52 supertypic group to specific loci allow comparisons between products of known alleles and between products of distinct loci. beta I allelic products showed approximately 11% divergence in the first domain, whereas beta I and beta III products showed 17% difference. These differences were clustered and found predominantly in the previously described variable regions (amino acid residues 9 through 13, 26 through 38, and 67 through 74). These data, coupled with the finding of shared variable regions among different DR beta chains, suggest gene conversion as a means of generating polymorphism in the beta I alleles. In contrast, the beta III allelic products showed less than 1% amino acid and nucleotide divergence in the first domain. These differences were outside the variable regions, and attributable to single nucleotide changes. The polymorphism at the beta I locus and the conservation at the beta III locus suggest selective pressure conserving the beta III locus and/or generating polymorphism at the beta I locus, and further suggest that gene conversion may be acting unidirectionally from beta III to beta I.
A synthetic analogue of Escherichia coli lipoprotein, tripalmitoyl pentapeptide, constitutes a potent immune adjuvant.
Authors: Lex A , Wiesmüller K H , Jung G , Bessler W G
Published: December 2022

Lipoprotein from the outer membrane of Escherichia coli and other Enterobacteriaceae constitutes a potent B lymphocyte mitogen and polyclonal activator in various species. Tripalmitoyl pentapeptide (S-(2,3-bis-(palmitoyloxy)-(2RS)-propyl)-N-palmitoyl-(R)-cysteinyl -(S)-seryl-(S)-seryl-(S)-asparaginyl-(S)-alanine) is a synthetic analogue of the N-terminal part of lipoprotein and has, in all assays tested, a biologic activity similar to native lipoprotein. It also exhibits a strong adjuvant activity in vitro: In the presence of 3.3 to 33.3 micrograms/ml of tripalmitoyl pentapeptide, the stimulation of the primary antibody response toward underivatized sheep red blood cells (SRBC) and toward trinitrophenylated (TNP-) SRBC was markedly enhanced, as measured by a direct hemolytic plaque assay. At optimal mitogen- and antigen-doses, plaque formation was increased up to 100-fold, and at suboptimal doses (0.03 to 0.3 microgram/ml) a 10- to 60-fold increase of plaque numbers was achieved. In the presence of tripalmitoyl pentapeptide, the antigen-specific IgM response was increased about sevenfold and the IgG response was augmented about 10-fold, as measured by ELISA. Similarly, in the secondary in vitro response to TNP-SRBC, a 7 to 10-fold enhancement of the antibody titer was obtained in the presence of the adjuvant. The application of tripalmitoyl pentapeptide and antigen had to occur concurrently in order to achieve a strong adjuvant effect. Addition of tripalmitoyl pentapeptide to the cell cultures 1 day after or 1 day before antigen application had no significant positive effect, and in several instances a decrease in antibody production was found. Thus, tripalmitoyl pentapeptide, a well-characterized synthetic product available in major amounts, constitutes a potent immune adjuvant for potential animal and clinical use.
Coexistence of a chemotactic factor and a retroviral P15E-related chemotaxis inhibitor in human tumor cell culture supernatants.
Authors: Wang J M , Cianciolo G J , Snyderman R , Mantovani A
Published: December 2022

Two sets of seemingly contradictory evidence have been reported concerning the effects of tumor cell products on the regulation of monocyte migration in vitro and presumably the extravasation of macrophages into tumors in vivo. The present study was designed to explore the relationship between chemotactic and anti-chemotactic products related to tumor cells: a tumor-derived chemotactic factor (TDCF) and retroviral P15E-related inhibitor(s) of chemotaxis. Culture supernatants of the human 8387 sarcoma and SW626 ovarian carcinoma were depleted of P15E-related antigens with immobilized anti-P15E monoclonal antibodies. This treatment produced a significant and consistent increase of the polarizing and chemotactic activity in the tumor cell supernatants. The material eluted from Sepharose-bound anti-P15E antibodies was devoid of chemotactic and polarizing activity and suppressed the polarization and migration of monocytes in response to chemoattractants. These results demonstrate the coexistence in culture supernatants of two human tumor cell lines of factors with opposite influences on monocyte chemotaxis. The data suggest that the entry of monocytes into neoplastic tissue may be regulated by the interplay of chemotactic and anti-chemotactic principals produced by tumor cells.
Characterization and activity of contrasuppressor T cells induced by type III pneumococcal polysaccharide.
Authors: Braley-Mullen H
Published: December 2022

Optimally immunogenic amounts of type III pneumococcal polysaccharide (S3) activate a population of contrasuppressor T cells (Tcs), which have been shown to play an important role in the induction of anti-S3 antibody responses. These Tcs belong to a unique T cell subset that has the surface phenotype Lyt 1+2- L3T4- I-J+ I-A+. These Tcs are also cyclophosphamide (Cy)-sensitive and sensitive to antilymphocyte serum (ALS) and mitomycin C. Tcs have antigen-binding receptors, indicating that any interactions of Tcs with B cells or T suppressor cells (Ts) (both of which also have antigen-binding receptors) must be via an antigen bridge rather than an idiotype-anti-idiotype interaction. Tcs are also Igh restricted in their action. Contrasuppression is manifest only when the Tcs are Igh compatible with both the Ts and the responding B cells. Tcs apparently mediate their effects by releasing a soluble factor, since a soluble factor extracted from Tcs is able to abrogate the effects of S3-specific Ts.