bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of a T cell-derived b cell growth factor distinct from interleukin 2.
Authors: Howard M , Farrar J , Hilfiker M , Johnson B , Takatsu K , Hamaoka T , Paul W E
Published: June 2004

We report here a factor (B cell growth factor) found in induced supernatants of the mouse thymoma EL4 that co-stimulates with anti-IgM antibodies in short-term cultures of purified B lymphocytes to induce polyclonal B cell proliferation but not antibody-forming cell production. The factor is not mitogenic for resting B cells and interacts with anti-IgM-activated B cells in a non-H-2-restricted manner. Absorption studies and molecular weight analysis reveal the factor is distinct from interleukin 2. This factor synergises with antigen, interleukin 2, and an interleukin 2-free, B cell growth factor-free T cell supernatant that contains T cell-replacing factor to produce erythrocyte-specific plaque-forming cells in cultures of highly purified B cells.
Role of the thymus in directing the development of a subset of B lymphocytes.
Authors: Mond J J , Scher I , Cossman J , Kessler S , Mongini P K , Hansen C , Finkelman F D , Paul W E
Published: June 2004

In an effort to evaluate the role of the thymus in influencing the development of Lyb-5- B lymphocytes, mice expressing both the xid and nu gene defects were studied. Mice expressing either of these defects respond to both trinitrophenylated Brucellus abortus and lipopolysaccharide; whereas mice with the combined defect show markedly suppressed responses. The other abnormalities included: (a) greater than 80 percent diminution of serum Ig levels; (b) significant increase in the number of sIgM+ sIgD- B lymphocytes; (c) reduced expression of IgD on sIgD+ cells; and (d) a strikingly abnormal histology of their lymphoid tissue. Because nu/nu mice that do not express the xid defect appear relatively normal, it would suggest that the development of Lyb-5- B lymphocytes require a thymic influence for normal maturation, whereas, Lyb-5+ B lymphocytes are relatively independent of such influences.
Intragenic recombination in an E beta gene for a murine Ia antigen.
Authors: Plunkett M L , Coligan J E , David C S , Freed J H
Published: June 2004

The recombinant strain D2.GD was originally typed as I-Ad by serological methods. Indeed, the A alpha and A beta chains of the I-A antigens appear to exhibit normal behavior by the criteria of serology and two dimensional gel analysis. However, the E beta chain encoded by the I-A subregion of this strain, one of the two components of the plasma membrane located I-E antigens produced in D2.GD X A.TFR5)F1 animals, has been demonstrated to be the product of an intragenic recombinational event between E beta genes from the d and b haplotypes. Sequence analysis suggests that the amino-terminal portion of the Eg2 beta chain is derived from the d haplotype and, therefore, that the coding strand for this gene is oriented centromeric leads to telomeric (5' to 3' direction). Finally, these data combined with the data of Rose and Cullen (17) allow the ordering of the genes within the I-A subregion as (H-2K), A alpha, A beta, E beta ... (H-2D).
Bone marrow transplantation across major histocompatibility barriers. V. Protection of mice from lethal graft-vs.-host disease by pretreatment of donor cells with monoclonal anti-Thy-1.2 coupled to the toxin ricin.
Authors: Vallera D A , Youle R J , Neville D M , Kersey J H
Published: June 2004

A new method has been devised to eliminate T cells from murine bone marrow grafts across major histocompatibility barriers and thus prevent graft-vs.-host disease (GVHD). The method utilizes a monoclonal antibody directed at the Thy-1.2 antigen but is complement independent. To make anti-Thy-1.2 toxic, the antibody is covalently linked to the toxin ricin. Ricin ordinarily binds, enters, and kills cells through receptors containing galactose. The hybrid protein, anti-Thy-1.2-ricin, can enter and kill cells via the Thy-1.2 receptor. In the presence of lactose the usual entry route for ricin is largely blocked and the hybrid is shown to be a highly selective reagent that is T cell specific in its inhibition of mitogen-stimulated splenocytes. We have used a model of severe and fatal GVHD where BALB/c splenocytes and bone marrow cells are given to irradiated C57BL/6 recipients. Over 90% of these mice die by day 70, exhibiting signs of GVHD. When donor cells are pretreated with 0.5 microgram/ml of anti-Thy-1.2-ricin plus 200 mM lactose before injection, 10 of 11 animals survive through day 70 without signs of GVHD. These studies demonstrate that ricin linked to monoclonal antibodies may have utility related to the prevention of GVHD in human bone marrow transplantation.
Studies of defective tolerance induction in NZB mice. Evidence for a marrow pre-T cell defect.
Authors: Laskin C A , Smathers P A , Reeves J P , Steinberg A D
Published: June 2004

NZB mice manifest a defect in tolerance induction by deaggregated heterologous gamma globulins. We have used an adoptive transfer system to study the defect. Thymectomized, intact, or thymectomized recipients given thymic epithelial grafts were studied after lethal irradiation and reconstitution with NZB, DBA/2, or (NZB x DBA(F1 marrow depleted of mature T cells. NZB thymocytes were responsible for the tolerance defect of NZB mice. The information for the defect was present in the NZB marrow prethymocyte. That defect could only be expressed when there was further maturation in association with a thymus. However, the normal DBA/2 thymic epithelium served as well as the abnormal NZB thymic epithelium. These studies resolve existing conflicts as to whether the NZB marrow or thymus is responsible for the loss of tolerance in association with autoimmunity.
T cells cooperating in the induction of delayed-type hypersensitivity act via the linked recognition of antigenic determinants.
Authors: Tucker M J , Bretscher P A
Published: June 2004

Culture conditions have been established that allow the induction of delayed-type hypersensitivity (DTH) precursor cells present in a cell population derived from unsensitized spleen cells only when antigen-specific, radioresistant, Thy-1-bearing helper cells are added. This specific cellular cooperation acts via the linked recognition of two determinants on the antigen; thus, cells primed to the protein antigen fowl gamma globulin (FGG) will only allow the induction of DTH reactivity against the second antigen, burro erythrocyte (BRBC), when the conjugate FGG-BRBC is present in the cultures. The requirement for physical linkage between the two antigens has been demonstrated by the observation that DTH to BRBC is induced when the conjugate FGG-BRBC is present and not when BRBC and FGG are given an uncoupled molecules.
Regulation of arachidonic acid metabolism by macrophage activation.
Authors: Scott W A , Pawlowski N A , Murray H W , Andreach M , Zrike J , Cohn Z A
Published: June 2004

Levels of zymosan-induced arachidonic acid (20:4) metabolism by peritoneal macrophages elicited with inflammatory agents and resident macrophages were similar. Thyioglycollate (THIO)-elicited macrophages represented the exception; however, the diminished metabolism by these cells was reproduced by exposing resident cells to 5 mg/ml THIO broth in vitro. In contrast, reduced prostaglandin synthesis by macrophages from mice variously treated with the immunologic agents, Corynebacterium parvum or Bacille Calmette Guérin (BCG), closely correlated with enhanced antitoxoplasma activity, one measure of macrophage activation. This relationship, although not causative, suggested that the capacity for 20:4 metabolism is a function of the macrophage activation state. Modulation of macrophage 20:4 metabolism in vivo apparently required factors in addition to lymphocyte-derived products. Treatment of resident macrophages in vitro with BCG lymphokine was without effect on 20:4 release or prostaglandin synthesis. Activated macrophages from animals inoculated i.p. with C. parvum exhibited reduced 20:4 release and also failed to metabolize 70% of the 20:4 released in response to a zymosan stimulus. Consequently, the quantities of 20:4 metabolites formed were significantly less than expected from 20:4 release. These activated macrophages displayed greatly reduced synthesis of prostacylcin and leukotriene C compared with other 20:4 metabolites. It appeared that factors that regulate macrophage 20:4 metabolism influence the level of the inducible phospholipase and synthetic enzymes for specific 20:4 oxygenated products.
Antigen-specific production of immune interferon by T Cells lines.
Authors: McKimm-Breschkin J L , Mottram P L , Thomas W R , Miller J F
Published: June 2004

Continuous cultures of T cells reactive to the hapten 4-ethoxymethylene-2-phenyloxazolone were tested for interferon production after antigenic stimulation in vitro. Induction of interferon was antigen-specific and also restricted by the I region of the major histocompatibility complex. Kinetics of antigen induced interferon production were different from those reported for mitogen induced synthesis.
Clearance of circulating DNA-anti-DNA immune complexes in mice.
Authors: Emlen W , Mannik M
Published: June 2004

DNA-anti-DNA immune complexes, produced from single-stranded DNA and IgG from a patient with systemic lupus erythematosus were cleared from the circulation of normal mice extremely rapidly, at a rate similar to the clearance of DNA alone. The initial clearance of these complexes was more rapid than the clearance of aggregated IgG, a surrogate immune complex containing a comparable number of IgG molecules, suggesting that the antigen (DNA) in the complexes significantly altered the clearance kinetics of the complexes. Analysis of the late clearance component of these complexes showed that anti-DNA is released back into the circulation after initial removal, and is then cleared at a rate similar to monomeric IgG. Whether this anti-DNA represents free antibody, or antibody bound to small nuclease digested DNA fragments, awaits further study.
Human autologous mixed lymphocyte reactivity is primarily specific for xenoprotein determinants adsorbed to antigen-presenting cells during rosette formation with sheep erythrocytes.
Authors: Huber C , Merkenschlager M , Gattringer C , Royston I , Fink U , Braunsteiner H
Published: June 2004

We present evidence that most T cells proliferating in response to autologous sheep erythrocyte (SRBC)-separated non-T cells (NT) cells are not specific for autoantigens but for antigens derived from xenogeneic sources. The conclusion was based on the following three observations. First, we found that NT cells isolated in the absence of xenoproteins by means of density gradient centrifugation on Percoll only weakly stimulated autologous T cells. Because this weak proliferation could not be expanded in restimulation experiments, its significance as an immune recognitive event remains questionable. NT cells isolated by the above method in the absence of xenogeneic determinants readily acquired stimulatory capacity after brief exposure to either SRBC or fetal calf serum. Second, restimulation of T memory cells generated in 1 degree autologous mixed lymphocyte reaction (AMLR) against SRBC-separated autologous NT cells was exclusively seen when NT cells exposed to or separated with xenoproteins were used for restimulation. Third, T memory cells generated against SRBC-separated autologous NT cells were specifically restimulated by autologous Percoll-separated NT cells that had been pulsed with a variety of xenogeneic mammalian sera. These xenogeneic determinants were preferentially recognized in context with autologous HLA-DR+ cells. From these findings and from our previous results that indicated an absolute requirement of HLA-DR+-adherent NT cells (8), we conclude that human AMLR primarily does not represent an autoantigen but a xenoantigen response that is genetically restricted by the HLA-DR type of the antigen-presenting cell.
Heterozygosity at Gm loci associated with humoral immunity to osteosarcoma.
Authors: Pandey J P , Shannon B T , Tsang K Y , Fudenberg H H , Camblin J G
Published: June 2004

Serum samples from 50 Caucasian patients with osteosarcoma were tested for the presence of antibodies to osteosarcoma-associated antigens (OSAA) and typed for nine Gm markers. A highly significant association was found between Gm 3;5,13,14 and unresponsiveness to OSAA, and between 1,3,17;5,13,14,21 and responsiveness to OSAA. These results suggest the existence of complementary immune response genes which in the heterozygous condition permit a response to OSAA.
Phenomenon of human T cells rosetting with sheep erythrocytes analyzed with monoclonal antibodies. "Modulation" of a partially hidden epitope determining the conditions of interaction between T cells and erythrocytes
Authors: Bernard A , Gelin C , Raynal B , Pham D , Gosse C , Boumsell L
Published: June 2004

Anti-D66 is a monoclonal antibody able to inhibit E-rosette formation of T cells both at 4 degrees C and at 37 degree C but that does not inhibit T cell rosette formation with neuraminidase or 2-amino-ethylisothiouronium bromide (AET)-pretreated E. As demonstrated by capping experiments, it defines an epitope, D66, that is directly involved in E-rosette formation. D66 is distinct from the epitope defined by 9.6 because 9.6, a previously defined "pan-T" monoclonal antibody, inhibits E(AET) rosette formation and because no cross-blocking occurred between both antibodies fixation. However, 9.6 and D66 are carried by the same molecule, as demonstrated by sequential immunoprecipitation assays performed on two different T cell lines. On the thymocyte surface, also, 9.6 and D66 are most probably carried by the same molecule, as indicated by cocapping and colysostripping experiments. D66 is present at higher densities on thymocytes and activated T cells than on peripheral blood T cells. Investigation of numerous T cell populations, both normal and malignant, showed a straightforward correlation between elevated D66 density and ability to form 37 degrees C stable E-rosettes. Neuraminidase treatment of thymocytes and peripheral blood lymphocytes forming E-rosettes unmasked a large fraction of D66 not readily accessible on their surface. These hidden D66 epitopes appear to be responsible for a surprising observation: the ability of anti-D66 to inhibit E-rosette formation could be totally reversed by fixation on anti-D66 of an antibody to mouse immunoglobulin or an Fab fragment anti-mouse immunoglobulin. This would induce microdisplacement with emergence of hidden D66, as documented by fluorometric studies. Finally, malignant T cells with a differentiative status of mature T cells, but forming no (or low numbers of) E-rosettes, could be induced both to display D66 and to form E-rosettes by neuraminidase treatment.
Non-H-2 restriction of expression of passively transferred delayed sensitivity.
Authors: Berche P A , North R J
Published: June 2004

The results of this study of allogeneic restriction of passively transferred delayed sensitivity to Listeria antigens serve to illustrate the complexity of in vivo models. They show that the H-2 restriction observed when delayed-type hypersensitivity was transferred between H-2-congenic strains was no more severe than the restriction observed when delayed-type hypersensitivity was transferred between parental and F1 mice and between different strains sharing the same H-2 haplotype. It is obvious that genes, in addition to those of the H-2 locus, can be responsible for allogeneic restriction in vivo.
Anaphylatoxin-mediated regulation of the immune response. I. C3a-mediated suppression of human and murine humoral immune responses.
Authors: Morgan E L , Weigle W O , Hugli T E
Published: June 2004

The C3a fragment of the third component of complement was found to have immunosuppressive properties. C3a is capable of suppressing both specific and polyclonal antibody responses. In contrast, C3a had no effect on antigen- or mitogen-induced B or T cell proliferative responses. The carboxy-terminal arginine is essential for C3a to exhibit its immunosuppressive properties. The serum carboxypeptidase inhibitor 2-mercaptomethyl-5-guanodinopentanoic acid, which prevents cleavage of the terminal arginine that would produce C3ades Arg-77, allowed us to assay the effects of C3a on in vitro immune response systems where serum is required. When the terminal arginine is removed from C3a, the resulting C3ades Arg-77 molecule is nonsuppressive. Helper T lymphocytes are the target of C3a-mediated suppression of the immune response. Substitution of T cells by soluble T cell factors was found to abrogate the C3a suppressive activity.
Complement receptor (CR1) deficiency in erythrocytes from patients with systemic lupus erythematosus.
Authors: Iida K , Mornaghi R , Nussenzweig V
Published: June 2004

This study reports quantitative information on the concentration of complement receptor for C3b and C4b (CR1) on erythrocytes from normal individuals and patients with immune complex disease. The measurements were performed by an immunoradiometric assay using monoclonal antibodies against CR1. The antibody specificity was confirmed by immunoprecipitation of CR1 from extracts of surface-labeled cells, by inhibition of rosette formation between B lymphocytes and the erythrocytes intermediate EAC14oxy23b, and by the characteristic distribution of the antigen among cells of human peripheral blood. The number of CR1 molecules in erythrocytes from 52 normal individuals was estimated as 1,410 +/- 620. No significant differences in CR1 levels were observed when individuals were grouped by sex, age, or blood groups. In patients with SLE and rheumatoid arthritis, the number of CR1 molecules per RBC was significantly lower, i.e., 600 +/- 307 and 903 +/- 417, respectively. CR1 levels were normal in asthmatics undergoing long-term treatment with prednisone. In SLE patients, significant correlations were found between CR1 levels, C4 hemolytic titers, and levels of circulating immune complexes. In two out of four patients with SLE, CR1 levels increased significantly during remission, showing that the deficiency is, at least in part, reversible. The deficiency in CR1 could be genetically controlled or could represent an epiphenomenon caused by the interaction of the receptor with a ligand present in the circulation of patients.
Bone marrow origin of decidual cell precursors in the pseudopregnant mouse uterus.
Authors: Kearns M , Lala P K
Published: June 2004

Decidual cells are considered to be the endproduct of a hormonally induced transformation of endometrial stromal cells of the uterus. However, the source of these precursors remains unknown. This study of evaluated the possibility of their bone marrow origin by an examination of the H-2 phenotype of decidual cells in pseudopregnant bone marrow chimeras. These chimeras were produced by repopulating lethally irradiated CBA/J female (H-2k) mice with bone marrow from (CBA/J x C57BL/6J) F1 female (H-2kb) mice. Pseudopregnancy was produced with a hormonal regimen followed by an oil-induced decidual stimulus. Chimerism was evaluated radioautographically by an identification of the donor-specific Kb phenotype on cells with an immunolabeling technique with monospecific anti-H-2 serum followed by radioiodinated protein A. The extent of chimerism as indicated by the degree of Kb labeling on decidual cells as well as macrophages contained within the decidual nodules was quantitatively compared with that seen on splenic lymphocytes. Fair to good chimerism, as reflected by labeling for the donor-specific marker (Kb), was seen on splenic lymphocytes and macrophages within the decidual nodules in 6 out of 11 animals. A similar level of chimerism was detected on decidual cells in all but one of these six, in which case this was low. One animal showed low chimerism in the spleen but good chimerism on the decidual cells. The remaining four mice were nonchimeric for all three cell types. These results indicate that decidual cells and macrophages appearing within the decidual nodules of pseudopregnant mice are ultimate descendants of bone marrow cells.
Abrogation by subsequent feeding of antibody response including IgE, in parenterally immunized mice.
Authors: Lafont S , André C , André F , Gillon J , Fargier M C
Published: June 2004

We have investigated the possibility of oral administration of ovalbumin (OVA) to prevent a secondary antibody response and interrupt reaginic antibody production. Repeated feeding seems necessary for both. Quality of results was dependent on the number of ingestions. Differences in abrogation of antibody response between mice strains were observed. Best results were obtained with AKR mice, good suppression was seen in C3H strain, and inconsistent results were obtained with DBA/2. 10 OVA oral doses were necessary to prevent a secondary antibody response in parenterally immunized mice, but 4 doses interrupted reaginic production in sensitized AKR mice. These results demonstrate that antigen feeding can prevent a secondary antibody response and interrupt reaginic antibody production.
Selective inhibition of human T cell cytotoxicity at levels of target recognition or initiation of lysis by monoclonal OKT3 and Leu-2a antibodies.
Authors: Landegren U , Ramstedt U , Axberg I , Ullberg M , Jondal M , Wigzell H
Published: June 2004

Out of a panel of seven monoclonal antibodies with affinity for human lymphoid cells, three were shown to prevent cytotoxic T cell activity, whereas none affected natural killer cell activity when applied without complement. Anti-OKT3 and anti-Leu-2a, with affinity for all T cells and the cytotoxic/suppressive subset, respectively were both shown to inhibit T killing by their interaction with the effector cell. For anti-OKT3, the inhibition remained after free antibody was washed away. Anti-Leu-2a, in contrast, induced a rapidly reversible inhibition. Using a single cell assay, anti-OKT3 was shown to reduce the lytic ability without affecting target cell binding, whereas anti-Leu-2a prevented the effectors from binding target cells.
Down-regulation of mannosyl receptor-mediated endocytosis and antigen F4/80 in bacillus calmette-guerin-activated mouse macrophages. Role of T lymphocytes and lymphokines
Authors: Ezekowitz AB , Gordon S
Published: June 2004

Bacillus Calmette-Guerin (BCG) infection alters the surface and endocytic properties of mouse peritoneal macrophages (PM) compared with thioglycollate- elicited (TPM) or resident PM (RPM). Expression of Ia antigen (Ag) is enhanced up to fourfold, but plasma membrane receptors that mediate binding and uptake of mannosyl/fucosyl-terminated glycoconjugates (MFR), Fc receptors, and the macrophage (mφ)-specific Ag F4/80 are reduced by 50-80 percent. Levels of Mac-1 remain relatively stable. These changes are accompanied by enhanced secretion of O(2)(-), after further stimulation with phorbyl myristate acetate, and of plasminogen activator. Both these products are released by TPM, but not RPM. The characteristic surface phenotype of BCG-PM can also be induced by injection of C. parvum, another mφ- activating agent, but not by thioglycollate broth, lipopolysaccharide, or proteose peptone. Purified protein derivative (PPD) and N-acetylmuramyl-L- alanyl-D-isoglutamine. 2H(2)0 are soluble agents with partial activity.

Alteration of mφ markers by BCG infection depends on T lymphocyte function, although studies with nude mice indicate that other pathways may also serve to modify the surface of the mφ. Mφ from uninfected animals displayed all markers of activation after adoptive transfer of specifically-sensitised lymphocytes with PPD, intraperitoneally, or after co- cultivation. Treatment of primed lymphocytes with anti-Thy-1 antibody and complement ablated this effect. Lymphokines obtaned by Ag or mitogen stimulation induced similar changes in TPM and RPM. Mannose-specific endocytosis decayed rapidly, time 1/2 approximately equal to 16 h and stabilized at approximately 25 percent of control values. Single-cell analysis showed that residual MFR activity was uniform in the target population. Loss of Ag F4/80 after activation by lymphocyte and PPD was less marked than after infection (35 percent vs 80 percent), unlike MFR activity, which declined to a similar extent. Induction of mφ Ia by lymphokine reached a peak after 2-3 d and was lost within 2 d of its removal. Recovery of MFR and F4/80 was incomplete under these conditions.

These studies establish that activated mφ known to display enhanced antimicrobial/anticellular activity express markedly different surface properties distinct from elicited or resident cells. The role of antigen- stimulated T cell products in regulating mφ function is confirmed, and down-regulation of mannosyl-receptor-mediated endocytosis provides a sensitive, quantitative, and cell-specific new marker to study their properties and mechanism of action. Extensive, but selective remodeling of mφ plasma membrane structure could play an important role in controlling recognition and effector mechanisms of the activated mφ.
A spontaneous rheumatoid arthritis-like disease in MRL/l mice.
Authors: Hang L , Theofilopoulos A N , Dixon F J
Published: June 2004

MRL/l mice spontaneously develop an arthritis very similar in many respects to human rheumatoid arthritis. A detailed morphologic and serologic analysis of this disease revealed the following: (a) a 75% incidence of synovial and periarticular inflammation, very similar to human rheumatoid arthritis, in 5-6 mo-old females, (b) close associations between presence of joint inflammation and subsynovial and/or periarticular vasculitis, and (c) a close correlation between presence of circulating IgM rheumatoid factor (RF) and demonstrable synovial and/or joint pathology, i.e., 95% of mice with significant levels of IgMRF had synovitis and/or arthritis.
Helper T cells for cytotoxic T lymphocytes need not be I region restricted
Authors: Raulet DH , Bevan MJ
Published: June 2004

We investigated the antigenic requirements for restimulation of H-2- restricted cytolytic T lymphocytes (CTL) in vitro to determine whether H-2 I region-restricted helper T cells are required in these responses. In one set of experiments, we studied the in vitro response of (responder x nonresponder)F(1) female T cells to the male antigen H-Y. We chose to examine this response because it has been suggested that the defect in nonresponder strains is a failure of helper T cells to recognize H-Y in association with nonresponder I region determinants. However, we find that nonresponder male stimulator cells are as effective as F(1) male stimulator cells at inducing H-Y-specific CTL responses. This finding calls into question reports that secondary CTL responses to H-Y are dependent upon the activation of H-Y- specific helper T cells restricted to responder type I region determinants.

In a second set of experiments, we examined the requirements for restimulation of H-2-restricted T cells specific for minor-histocompatibility antigens from long-term mixed lymphocyte cultures. These cultures were established by repeatedly restimulating cultures of specific T cells with H- 2-matched stimulator cells expressing foreign minor histocompatibility antigens. We found that H-2D-restricted T ceils, including CTL, could be restimulated with cells that were matched with the responding cells at only the D region genes. This response did not appear to result from positive allogeneic effects or from antigen processing and "representation" by responder type APC that might contaminate the cultures. Thus, we find no evidence for a requirement for I region-restricted helper T cells in these CTL responses. However, helper T cells are required because we find that CTL lines derived by limit-dilution cloning from these long-term MLC are absolutely dependent upon exogenous helper factors for growth. The most simple interpretation of these results is that the helper cells are restricted to H-2 antigens other than I region antigens or to antigens that code outside of the H-2 complex.

Finally, we show that factor-dependent CTL lines must recognize their specific antigen to proliferate, even in the presence of exogenous factors. The requirement of activated CTL for antigen to proliferate provides an explanation for how specific CTL can be selectively enriched in MLC by specific antigen stimulation. Furthermore, it is at variance with reports that memory CTL or activated CTL require only interleukin 2 for restimulation.
Lymphokine-activated killer cell phenomenon. Lysis of natural killer-resistant fresh solid tumor cells by interleukin 2-activated autologous human peripheral blood lymphocytes.
Authors: Grimm E A , Mazumder A , Zhang H Z , Rosenberg S A
Published: June 2004

Activation in lectin-free interleukin 2 (IL-2) containing supernatants of peripheral blood mononuclear leukocytes (PBL) from cancer patients or normal individuals resulted in expression of cytotoxicity toward 20 of 21 natural killer (NK)-resistant fresh solid tumor cells tested. Fresh solid tumor cells were resistant to NK-mediated lysis in 10 autologous patients' PBL-tumor interactions, and from 17 normal individuals tested against 13 allogeneic fresh tumors. Culture of PBL in IL-2 for 2-3 d was required for the lymphokine activated killers (LAK) to be expressed, and lytic activity toward a variety of NK-resistant fresh and cultured tumor targets developed in parallel. Autologous IL-2 was functional in LAK activation, as well as interferon-depleted IL-2 preparations. Irradiation of responder PBL before culture in IL-2 prevented LAK development. Precursors of LAK were present in PBL depleted of adherent cells and in NK-void thoracic duct lymphocytes, suggesting that the precursor is neither a monocyte nor an NK cell. LAK effectors expressed the serologically defined T cell markers of OKT.3, Leu-1, and 4F2, but did not express the monocyte/NK marker OKM-1. Lysis of autologous fresh solid tumors by LAK from cancer patients' PBL was demonstrated in 85% of the patient-fresh tumor combinations. Our data present evidence that the LAK system is a phenomenon distinct from either NK or CTL systems that probably accounts for a large number of reported nonclassical cytotoxicities. The biological role of LAK cells is not yet known, although it is suggested that these cells may be functional in immune surveillance against human solid tumors.
Accessory and stimulating properties of dendritic cells and macrophages isolated from various rat tissues
Authors: Klinkert WEF , LaBadie JH , Bowers WE
Published: June 2004

Single cell suspensions of rat lymphoid and nonlymphoid tissues were fractionated on discontinuous gradients of bovine serum albumin into high density and low density subfractions. In general, accessory activity required for responses of periodate-treated T lymphocytes was recovered only in a low density population containing a small percent of the total fractionated cells from lymph nodes, spleen, liver, skin, and peritoneal exudates. Further purification always led to an increase of both accessory activity and number of dendritic cells present in nonrosetting and nonadherent populations. After purification, a high recovery of the total accessory activity was found in fractions that contained a high percentage of dendritic cells resulting in a more than 1,000-fold enrichment in accessory activity per cell. No other fraction obtained during the purification contained significant accessory activity. In all cases, macrophage-enriched populations lacked accessory cell activity. With the exception of peritoneal exudate cell preparations, which contained an inhibitory cell, the level of accessory activity in a given population was always found to be a function of the number of dendritic cells present.

Dendritic cells from all sources were nonadherent, nonphagocytic, radio- resistant, and nonspecific esterase negative. They expressed Ia antigens and lacked Fc receptors. Both epidermal and lymph node dendritic cells contain Birbeck granules, subcellular structures previously described only for Langerhans cells.

Accessory activity requires viable dendritic cells but is unaffected by 1,000 rad of γ-irradiation. However, ultraviolet irradiation abolished the activity of accessory cells. The cells that responded to periodate were IgG-negative T cells, whereas IgG-positive B cells could not be stimulated under the same conditions. Only periodate-treated T cells and dendritic cells were needed for responses to occur; removal of virtually all macrophages from these purified preparations had no effect. Dendritic cells were also required as stimulators in mixed leukocyte cultures, whereas macrophages, even though Ia positive, were inert.
Enhanced production of murine interferon gamma by T cells generated in response to bacterial infection.
Authors: Havell E A , Spitalny G L , Patel P J
Published: June 2004

Spleen cell cultures derived from animals infected 6 d earlier with Listeria monocytogenes produced 10-20-fold more murine interferon gamma (MuIFN gamma) than spleen cells from nonimmune mice in response to stimulation with T cell mitogens. A striking temporal association was found between the enhanced synthesis of MuIFN gamma and the development of anti-Listeria immunity in that both the potential for increased MuIFN gamma production and the generation of Listeria-protective T cells developed and then decayed in unison. Treatment of spleen cells with monoclonal anti-Thy-1.2 plus complement virtually abolished the ability of cells from Listeria-immune mice to synthesize MuIFN gamma. The T cells producing MuIFN gamma were found to be more susceptible to complement-mediated lysis with monoclonal anti-Lyt-1.2 than with monoclonal anti-Lyt-2.2. The production of MuIFN gamma was not affected by treating spleen cells with anti-IgG antisera or with a monoclonal antibody directed against I-A specificities. MuIFN gamma was detected 4 h after the beginning of mitogenic stimulation of spleen cell cultures, and peak levels of MuIFN gamma were reached by 18 h. The IFN synthesized by mitogen-induced spleen cells derived from Listeria-immune mice were relatively labile at pH 2.0 and neutralized by a rabbit anti-MuIFN gamma serum but not by an antiserum having specificities for MuIFN alpha and MuIFN beta. The apparent molecular weight of the MuIFN gamma, as estimated by molecular sieving on a Bio-gel P-60 column, was estimated to be 38,000, and the isoelectric point as determined by chromatofocusing was extremely heterogeneous, ranging between pH 5.0 and pH 7.0.
Molecular organization of C9 within the membrane attack complex of complement. Induction of circular C9 polymerization by the C5b-8 assembly
Authors: Podack ER , Tschoop J , Muller-Eberhard HJ
Published: June 2004

Evidence has been presented suggesting that during assembly of the membrane attack complex (MAC) of complement, the C5b-8 complex induces polymerization of C9. The C9 polymer was detected by sodium dodecyl sulfate (SDS) gel electrophoresis of MAC isolated from complement-lysed erythrocytes. It resembled the previously described polymerized C9 (poly C9) produced from isolated monomeric C9 by prolonged incubation at 37 degrees C in that it was resistant to dissociation by SDS and reducing agents and had an apparent molecular weight of approximately 1.1 million. The presence of poly C9 in the MAC was further supported by the expression of identical neoantigens by the MAC and poly C9 and by the high C9 content of the MAC relative to its other constituents. Isolated C8 in solution was found to have a single C9-binding site. In mixture, the two proteins formed a reversible equimolar complex that had a sedimentation coefficient of 10.5S. In contrast, a single, cell-bound C5b-8 complex was found to bind up to 12-15 C9 molecules and clusters of C5b- 8 bound 6-8 C9 molecules per C8 molecule. In either case, typical ultrastructural membrane lesions were observed, suggesting that the membrane lesion is identical with the tubular poly C9 consisting of 12-16 C9 molecules, and that the MAC can have either the composition (C5b-8)polyC9 or (CSb-8)(2)polyC9. When C9 input was restricted so that the molar C9/C8 ratio was less than or equal to 3, C9-induced aggregates of C5b-8 were observed but virtually no circular membrane lesions were found. We suggest, therefore, that C9, at low dosage, causes cross-linking of multiple C5b-8 complexes within the target membrane and that, at high dosage, C9 is polymerized by C5b-8 to form a transmembrane channel within the MAC assembly. It is primarily the C9 polymer that evokes the ultrastructural image of the MAC or of membrane lesions caused by complement.
Restricted nucleocytoplasmic relationship in activation of T and B lymphocytes.
Authors: Watanabe T , Eda Y , Ohara J
Published: June 2004

Nuclei of murine T lymphocytes or B lymphocytes were purified and transferred into lethally irradiated whole spleen cells or B or T lymphocytes by means of polyethyleneglycol-mediated cell fusion. Transfer of lymphocyte nuclei could save the irradiated cells from cell death, and such reconstituted cells could respond to mitogens. The present study showed that nuclei of T cells could be activated in the concanavalin A-stimulated T cell cytoplasms but not in the lipopolysaccharide-stimulated B cell cytoplasms. On the other hand, nuclei of B cells were activated in the lipopolysaccharide-stimulated B cells but not in the concanavalin A-stimulated T cell cytoplasms. These data suggested that a specific interaction between cytoplasm and nucleus might exist in the activation of nuclei of each lymphocyte subset.
Immunoglobulin secretion in the human autologous mixed leukocyte reaction. Definition of a suppressor-amplifier circuit using monoclonal antibodies.
Authors: Gatenby P A , Kotzin B L , Kansas G S , Engleman E G
Published: June 2004

The induction of immunoglobulin (Ig) synthesis in the autologous MLR has an absolute requirement for helper/inducer (Leu-3) T cells, whereas an excess of suppressor/cytotoxic (leu-2) cells suppresses the response. The current study was an effort to assess the immunoregulatory potential to T cells activated in the autologous mixed-leukocyte response (MLR). T cells were cultured with autologous non-T cells for 8-9 d, after which the activated T cells were fractionated into subsets with monoclonal antibodies to T cell markers and HLA-DR antigen. Each population was co-cultured in fresh autologous MLR, and on the 8th day of culture, Ig-secreting cells were measured in a reverse hemolytic plaque assay. The results show that activated Leu-2, DR+ T cells, but neither Leu-2, DR- nor Leu-3 T cells, were at least 50 times more potent as suppressors of IgM and IgG synthesis than fresh Leu-2 cells alone. The activation of this Leu-2, DR+ subpopulation required Leu-3 cells in the primary culture. Furthermore, in the absence of Leu-2 cells in the second culture, little or no suppression was observed, suggesting that the Leu-2, DR+ cells act to amplify or induce suppressor effects of fresh Leu-2 cells. This indicates that at least two distinct subpopulations of Leu-2 cells are required for maximal suppression of an immune response, and that immunoregulatory circuits analogous to those described in the mouse exist in man.
Enhancement of human blood eosinophil cytotoxicity by semi-purified eosinophil colony-stimulating factor(s).
Authors: Dessein A J , Vadas M A , Nicola N A , Metcalf D , David J R
Published: June 2004

Purified human blood eosinophils, when incubated in human placental conditioned medium (a source of colony-stimulating factors) [CSF]) demonstrate an enhanced ability to damage antibody- or complement-coated schistosomula. This enhancement represents a 4- to 10-fold increase of eosinophil schistosomicidal ability and a 10-fold lowering of the threshold for antibody or complement required in the killing reaction. The activity that enhances eosinophil cytotoxicity and the eosinophil colony-stimulating activity in the placental conditioned medium are eluted in the same fraction (CSF-alpha) after chromatography on Sephadex G-100 and phenyl-Sepharose columns, suggesting that these two activities might be associated with the same molecule. CSF-alpha enhances the adherence step of the killing reaction: antibody-coated larvae were frequently found covered by several layers of eosinophils in tubes containing CSF-alpha. Such a degree of adherence was rarely seen in control tubes lacking CSF-alpha. This enhancement of the eosinophil adherence is detectable 45-60 min after addition of CSF-alpha to the culture. It is not affected by washing the cells after a short time of preincubation with CSF-alpha, and it occurs in the absence of protein synthesis, whereas colony-stimulating activity requires continuous protein synthesis and ceases when CSF is removed from the culture. Finally, CSF-alpha enhances the temperature-dependent reaction that insures the irreversibility of eosinophil attachment to schistosomula. These observations suggest that eosinopoietic factors could be responsible for some of the modified properties of blood eosinophils in eosinophilic individuals.
Erythroleukemia induction by Friend leukemia virus. A host gene locus controlling early anemia or polycythemia and the rate of proliferation of late erythroid cells.
Authors: Shibuya T , Niho Y , Mak T W
Published: June 2004

This report confirms that the Fv-5 locus controls the types of erythropoiesis induced by Friend erythroleukemia virus (FLV) (21) and extends the study to investigate the mode of action of this locus. With the use of FLV obtained by a variety of procedures, we showed that the polycythemia spleen focus-forming component (SFFVp) was responsible for the contrasting changes of hematocrits observed in FV-Pp (polycythemia strain)-infected DBA/2 (Fv-5pp) or CBA (Fv-5aa) mice. These changes in hematocrits were found to be a direct result of the rise in circulating reticulocytes and erythrocytes in DBA/2 mice and a corresponding drop of these erythroid cells in CBA mice 2 wk after infection. Examination of the FV-P-induced cellular changes indicated that dramatic increase in erythropoietin (epo)-independent erythroid precursor (CFU-E*) cells was detected in the spleens and marrow of both strains of mice. The epo responsiveness of the CFU-E in the uninfected and FV-P-infected CBA and DBA/2 mice was also very similar. Similar to FLV-infected DBA/2 mice, the FV-P-infected CBA mice also developed tumorogenic cells (CFU-FV) relatively early after infection (4-6 wk). Study of the physiological and pathological changes in the marrows and spleens of these infected mice indicated that significant differences were found in the spleens of the two strains of mice. The percent of reticulocytes in the spleen cells of CBA mice remained between 10 and 20%, and level of the DBA/2 mice increased to approximately 50%. This higher rate of erythropoiesis was also reflected in the significantly higher rate of uptake of 59Fe in the spleens of the DBA/2 mice. These results suggest that the Fv-5 locus might control the hematocrit levels of these mice by regulating the rates of erythropoiesis in the spleen levels of these mice, probably by affecting the rate of proliferation of an erythroid cell or cells. The erythroid cell(s) affected is likely to be more mature than the erythroid progenitor, CFU-E, as the levels of CFU-E in these two strains of mice were similar. The hypothesis that Fv-5 may control the rates of proliferation of a late erythroid (cell(s) is also supported by the significantly higher spleen weights found in the infected DBA/2 (approximately 2.5 g/spleen) mice than in the CBA (approximately 1 g/spleen) strain.
Phagocytosis of senescent neutrophils by human monocyte-derived macrophages and rabbit inflammatory macrophages.
Authors: Newman S L , Henson J E , Henson P M
Published: June 2004

An in vitro system to investigate the ability of macrophages to recognize and ingest senescent polymorphonuclear neutrophils has been used that uses chromium-labeled neutrophils and staining for myeloperoxidase (MPO). Human monocyte-derived macrophages obtained from in vitro cultures were able to recognize "aged" but not freshly isolated 51Cr-labeled human neutrophils and ingest them. Freshly isolated monocytes did not exhibit this property. Because the aged neutrophils were greater than 95% viable, death did not appear to be a prerequisite for recognition and ingestion. Serum was not required for the aging of the neutrophils, and when serum was used, different concentrations did not appear to effect the aging process; that is, neutrophils aged in different concentrations of serum were ingested equally. Phagocytosis of senescent neutrophils by macrophages occurred in a time-dependent manner and was also dependent on the number of neutrophils added. Monocyte-derived macrophages first exhibited the ability to phagocytose senescent neutrophils on the 3rd d of culture, with the percentage of active macrophages increasing through day 7. In experiments with rabbit mononuclear phagocytes, immune complex-induced inflammatory macrophages from the lung but not resident bronchoalveolar macrophages or peripheral blood monocytes were found to be capable of recognition and ingestion of senescent rabbit neutrophils. These data suggest that the monocyte maturation process, akin to that seen during inflammation, is necessary in vitro before macrophages recognize and remove senescent neutrophils.
I-J restrictions on the activation and interaction of parental and F1-derived TS3 suppressor cells.
Authors: Minami M , Furusawa S , Dorf M E
Published: June 2004

An experimental system was developed to independently analyze the H-2 and Igh genetic restrictions at two steps of the 4-hydroxy-3-nitrophenylacetyl hapten (NP) suppressor cell pathway. This experimental system allowed genetic analysis of the activation of TS3 cells by hybridoma-derived TsF2 and independent analysis of the genetic restrictions that controlled the interaction of the TS3 cells with their target population. Thus, TS3 cells were activated in vitro with monoclonal H-2b or H-2k-derived TsF2. The activated TS3 cells were then adoptively transferred to TS3-depleted (cyclophosphamide-treated) recipients of various genotypes. When the TS3-containing lymph node population was activated in vitro for 2 h, suppressive activity was only noted in combinations of TSF2, TS3, and recipients that were matched at both the I-J and Igh gene complexes. The data indicate that TsF2 can activate TS3 cells and that both the activation and the interaction of TS3 cells are I-J and Igh restricted. Using (B10 x B10.BR)F1 mice as TS3 donors, we noted that H-2b-derived TsF2 activated these F1 TS3 cells to suppress NP-specific cutaneous sensitivity responses in H-2b but not in H-2k recipients. Reciprocal experiments using H-2k-derived TsF2 demonstrated that only an H-2k-restricted population was activated in the F1-derived TS3 cells. The simplest explanation to account for these observations is that two distinct populations, each of which is restricted to a parental I-J determinants, exists in the heterozygous F1 TS3 population. Furthermore, we demonstrated that both I-Jb and I-Jk determinants are expressed on F1-derived TS3 cells. These observations are discussed in terms of the mechanisms involved in immunoregulation.