bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation by interleukin 2 of interleukin 2 receptors and gamma-interferon synthesis by human thymocytes: augmentation of interleukin 2 receptors by interleukin 2.
Authors: Reem G H , Yeh N H
Published: December 2022

The role of interleukin 2 (IL 2) on the expression of IL 2 receptors and on the synthesis of gamma-interferon (gamma-IFN) by human thymocytes was investigated. Human thymocytes isolated from specimens obtained during cardiac surgery of infants and children were induced with one or all of the following agents: IL 2, concanavalin A (Con A), and 12-O-tetradecanoylphorbol 13-acetate (TPA). The expression of IL 2 receptors and gamma-IFN titers were determined. The results indicate that thymocytes cultured in complete medium do not express receptors for IL 2, nor did IL 2 by itself induce the expression of IL 2 receptors. Con A induced the expression of IL 2 receptors by a moderate number of the thymocyte population and induced the synthesis of low amounts of gamma-IFN. Preincubation of thymocytes with TPA increased the response to Con A; both the number of thymocytes expressing receptors and the synthesis of gamma-IFN were increased. Addition of IL 2 to these cultures further augmented the expression of IL 2 receptors and gamma-IFN synthesis and resulted in the optimal expression of IL 2 receptors and maximal gamma-IFN synthesis. The expression of IL 2 receptors could be detected within 24 hr and preceded the induction of proliferation; it was therefore probably not due to the clonal expansion of a population of receptor-bearing thymocytes. Conversely, inhibition of IL 2 synthesis with dexamethasone (Dex) by thymocytes activated with Con A, or inhibition of the function of IL 2 receptors by anti-Tac, resulted in a decrease in the number of IL 2 receptor-bearing thymocytes activated with Con A, or inhibition of the function of IL 2 receptors by anti-Tac, resulted in a decrease in the number of IL 2 receptor-bearing thymocytes and of gamma-IFN synthesis. Thymocytes activated with TPA and Con A were more resistant to the inhibitory effects of Dex on the expression of IL 2 receptors than thymocytes activated with Con A alone. Maximal inhibition of the expression of IL 2 receptors and of gamma-IFN synthesis was achieved as a result of the synergistic effect of anti-Tac with Dex. Therefore, when IL 2 was prevented from binding to the receptors, and IL 2 synthesis was inhibited, the number of thymocytes expressing IL 2 receptors was sharply reduced and gamma-IFN synthesis was markedly inhibited.(ABSTRACT TRUNCATED AT 400 WORDS)
Effect of recombinant IL 2 and gamma-IFN on proliferation and differentiation of human B cells.
Authors: Nakagawa T , Hirano T , Nakagawa N , Yoshizaki K , Kishimoto T
Published: December 2022

The effects of IL 2 and gamma-IFN on the activation of human B cells was studied with recombinant IL 2 and gamma-IFN. BCDF-responsive B lymphoblastoid cell lines and highly purified human B cells were employed as target B cells. IL 2 or gamma-IFN did not induce any IgG or IgM secretion in the B cell lines CESS and SKW6-CL4, in which IgG and IgM were inducible with conventional T cell factor(s). IL 2 alone did not induce the optimum production of Ig, but did induce proliferation in the SAC-stimulated B cell population. No Leu-1-, Leu-4-, or Leu-7-positive cells were detected in B cell populations that had been stimulated with SAC for 3 days. FACS analysis showed that a portion of the SAC-stimulated B cells (30%) were in the G2 or M stages by IL 2 stimulation. The addition of gamma-IFN together with IL 2 induced IgM and IgG secretion in SAC-stimulated B cells that was comparable with that induced by a conventional T cell factor(s). IL 2 induced proliferation not only in SAC-stimulated B cells but also in an anti-mu-stimulated B cell population. Stimulation of T cell populations with anti-mu and IL 2 did not induce significant proliferation, suggesting the direct effect of IL 2 on B cells. Double staining of anti-mu-stimulated B cells with anti-Ig and anti-Tac antibodies demonstrated that anti-mu stimulation induced an increased expression of Tac antigen on surface Ig-positive B cells. All of these results strongly supported the notion that IL 2 was one of the growth factors for B cells, and gamma-IFN was one of the differentiation factors for B cells.
Interleukin 2 enhances the natural killer cell activity of acquired immunodeficiency syndrome patients through a gamma-interferon-independent mechanism.
Authors: Rook A H , Hooks J J , Quinnan G V , Lane H C , Manischewitz J F , Macher A M , Masur H , Fauci A S , Djeu J Y
Published: December 2022

Patients with the acquired immunodeficiency syndrome (AIDS) exhibit a variety of disorders of cellular immunity, including a deficient ability to generate cytotoxic T cells and depressed levels of natural killer (NK) cell activity. Interleukin 2 (IL 2) in vitro can markedly augment these depressed immune functions. Because IL 2 can induce the release of interferon-gamma (IFN-gamma) from normal peripheral blood lymphocytes (PBL), and because IFN-gamma may play a role in the regulation of NK cell activity, this study was performed to determine if the IL 2 enhancement of the NK cell activity of patients with AIDS was an IFN-gamma-dependent effect. PBL from eight healthy heterosexual donors and from nine patients with AIDS were studied for their ability to release IFN-gamma in response to IL 2 at a concentration of 100 U/ml. After 60 hr of culture, the PBL of all eight healthy donors produced IFN-gamma with a mean titer of 113 U/ml (range 40 to 320 U/ml). In contrast, the PBL from only two of nine patients with AIDS released measurable amounts of IFN-gamma (40 U/ml each) in response to IL 2 with a mean titer of 13.5 U/ml for all nine. Although the PBL from patients with AIDS were deficient in their capacity to produce IFN-gamma in response to 100 U/ml of IL 2, significant enhancement of NK cell activity could be obtained after only 1 hr of PBL treatment with 10 U/ml of IL 2, with an optimal NK enhancing effect occurring at doses of 50 to 100 U/ml of IL 2. The use of an anti-IFN-gamma monoclonal antibody resulted in complete neutralization of the IFN released from the normal PBL cultured with IL 2, but failed to inhibit the IL 2 enhancement of NK cell activity. Exogenous IFN-gamma exhibited different kinetics of enhancement of NK cell activity when compared to IL 2, requiring substantially more than 1 hr of pretreatment of PBL. These results indicate that the PBL from patients with AIDS usually do not release IFN-gamma when cultured with IL 2, and that IL 2 enhancement of the depressed NK cell activity of these patients may be an IFN-gamma-independent event. These results may have important implications for the therapy of AIDS.
The isolation and characterization of the human suppressor inducer T cell subset.
Authors: Morimoto C , Letvin N L , Distaso J A , Aldrich W R , Schlossman S F
Published: December 2022

Immunization of mice with lower primate lymphoid cells has provided a useful strategy for raising monoclonal antibodies against functionally important surface determinants on human T lymphocytes. We have developed a monoclonal antibody, anti-2H4, which defines functionally unique human T cell subsets. This anti-2H4 antibody was reactive with approximately 42% of unfractionated T cells, 41% of T4+ inducer cells, and was reactive with approximately 54% of T8+ cytotoxic/suppressor population. Anti-2H4 was not reactive with human thymocytes, but reacted with subsets of peripheral blood B cells and null cells. This antibody subdivided peripheral blood T4+ cells into two functionally distinct populations. The T4+2H4+ subset proliferate well to concanavalin A (Con A) stimulation, but poorly to soluble antigen stimulation, and provides poor help to B cells for PWM-induced Ig synthesis. The T4+2H4- subset, in contrast, proliferates poorly upon stimulation with Con A, but well on exposure to soluble antigen, and provides a good helper signal for PWM-induced Ig synthesis. What is, perhaps, most important, the T4+2H4+ subset functions as the inducer of the T8+ suppressor cells. Previous attempts to define the latter subset of cells has relied heavily on the use of specific autoantibodies present in the sera of patients with juvenile rheumatoid arthritis (JRA) and systemic lupus erythematosus (SLE). The present results suggest that anti-2H4 antibody defines the human suppressor induced subset of lymphocyte previously described as T4+JRA+. Last, the results reemphasize the previously documented remarkable structural conservation of certain T cell-specific determinants on lymphocytes of phylogenetically distant primates.
Failure of bone marrow cells to reconstitute T cell immunity in graft-vs-host mice.
Authors: Lang P , Miller M W , Shearer G M
Published: December 2022

A chronic GVH reaction (detected by T cell immune deficiency) was induced in unirradiated, adult (C57BL/10 X B10.A)F1 mice by injecting them i.v. with 3 X 10(7) B10.A parental spleen cells. Thirty-four days later, attempts were made to reconstitute the GVH immune-deficient mice by whole-body irradiation and repopulation with bone marrow cells from normal syngeneic F1 mice. The reconstituted mice were tested for CTL responses 147 and 272 days after repopulation with normal F1 bone marrow. These GVH/chimera mice remained immunoincompetent for at least 272 days for CTL responses to hapten-self and H-2 allogeneic antigens.
T cell responses to Mls determinants are restricted by cross-reactive MHC determinants.
Authors: Lynch D H , Gress R E , Needleman B W , Rosenberg S A , Hodes R J
Published: December 2022

The studies presented here investigated the relationship between T cell recognition of MHC-encoded products and non-MHC-linked Mls determinants. The first aspect addressed whether Mls-reactive T cells recognize Mls-encoded products alone or in association with MHC-encoded determinants. Initial studies used Mlsa-specific T cell clones that were generated by repeated stimulation of C57BL/6 or B10.A(5R) spleen cells with DBA/2 lymphoid cells. These clones recognized Mlsa on cells expressing MHC products of the H-2b, H-2d, and H-2k haplotypes, but not the H-2q haplotype. Thus, these cloned T cells were found to recognize Mlsa products in association with public but demonstrably polymorphic H-2 determinants. The question of whether T cell clones that were specific for self-H-2 determinants (autoreactive) or soluble antigen plus syngeneic H-2 (antigen-specific) could also be stimulated by Mlsa determinants was also addressed. A substantial proportion of the antigen-specific or autoreactive T cell clones tested were stimulated by Mlsa determinants. Furthermore, stimulation of these clones by Mlsa was H-2 restricted. The pattern of H-2-restricted recognition of Mlsa by these clones was not distinguishable from that observed in the Mlsa-specific T cell clones, nor was it influenced by the primary specificity or H-2 restriction pattern of a given clone. Although these findings provide a means of explaining the observation that Mls-reactive T cells exist at extremely high precursor frequencies, they also raise questions regarding the nature of the receptor structures which are used by a single T cell in the recognition of two or more apparently distinct stimuli.
Frequency analysis of functional immunoglobulin C- and V-gene expression by mitogen-reactive B cells in germfree mice fed chemically defined ultra-filtered "antigen-free" diet.
Authors: Hooijkaas H , van der Linde-Preesman A A , Bitter W M , Benner R , Pleasants J R , Wostmann B S
Published: December 2022

The frequencies of lipopolysaccharide (LPS)-reactive B cells and their antibody specificity repertoire have been determined in the spleen and bone marrow (BM) of conventional (CV) and "antigen-free" C3H/HeCr mice of various ages. The antigen-free mice were germfree (GF)-raised and were fed an ultrafiltered solution of chemically defined (CD) low m.w. nutrients, and were thus devoid of exogenous antigenic stimulation. Spleen and BM cells were grown in a limiting dilution culture system that allows the growth and development of every newly formed LPS-reactive B cell into a clone of IgM-secreting cells which are capable of switching to other immunoglobulin (Ig) heavy chain isotypes (C-gene expression). The secretion of IgM and IgG1 was determined in the protein A plaque assay, whereas specific IgM antibody-secreting cells (V-gene expression) were detected in plaque assays specific for various heterologous erythrocytes and sheep red blood cells (SRBC) coupled with a number of different haptens. The absolute frequency of LPS-reactive B cells and their capacity to switch to IgG1-secretion was not significantly different in 8- to 12-wk-old and 52-wk-old GF-CD mice and their age-matched CV controls. Moreover, no differences were observed in the frequencies of antigen-specific B cells within the pool of LPS reactive B cells. These frequencies ranged from 1 in 20 to 1 in 50 for NIP4-SRBC and NNP2-SRBC, from 1 in 100 to 1 in 150 for NIP0.4-SRBC, from 1 in 50 to 1 in 100 for TNP30-SRBC, and from 1 in 1000 to 1 in 2000 for SRBC and horse red blood cells. Within the limitations of having determined the switching capacity of IgM to IgG1 only and having assessed only a minor fraction of the total B cell antibody-specificity repertoire, the data indicate that young and old GF-CD mice, although devoid of exogenous antigenic and/or mitogenic stimulation, generate B cells with a similar switching capacity and a similar IgM antibody specificity repertoire as CV mice.
Coexpression of T4 and T8 on peripheral blood T cells demonstrated by two-color fluorescence flow cytometry.
Authors: Blue M L , Daley J F , Levine H , Schlossman S F
Published: December 2022

Using two-color fluorescence flow cytometry, we were able to detect the presence of small numbers of T4+T8+ cells (about 3%) in freshly isolated peripheral T cell populations derived from normal healthy donors. Coexpression of T4 and T8 was predominantly found on large blastlike cells and appeared to be related to activation. Stimulation of peripheral T cells with concanavalin A (Con A) for 5 days resulted in the generation of up to 60% of T4+T8+ cells. Coexpression was accompanied by a twofold increase in the number of T8 antigenic sites per cell. The T4+T8+ cells in lectin-stimulated cultures expressed high levels of the activation antigens T9, T10, and the IL-2 receptor but lacked T6, an antigen found on a majority of stage II thymocytes. Coexpression of T4 and T8 appeared to be a transitory process, because prolonged culture of T cells in the absence of lectin resulted in the loss of the T4+T8+ phenotype. Our data suggest that T cell activation in peripheral blood results in the generation of a T4+T8+ cell population which is distinct from previously described thymic and peripheral blood cells. Because T4 and T8 molecules may interact directly with MHC antigens, coexpression of these molecules may have an important role in immune function.
Specificity of oligoclonal IgG bands in sera from chronic relapsing experimental allergic encephalomyelitis guinea pigs.
Authors: Mehta P D , Patrick B A , Wisniewski H M
Published: December 2022

The specificity of oligoclonal IgG in sera from chronic relapsing EAE guinea pigs was determined by using imprint electroimmunofixation. The response of oligoclonal IgG to spinal cord and Mycobacterium tuberculosis appeared to be equal in animals sacrificed during first remission and in those sacrificed after recovery from acute EAE. In contrast, in animals sacrificed during or after the first relapse, the oligoclonal IgG seems to be directed predominantly against spinal cord. In imprint electroimmunofixation, the oligoclonal IgG specific to spinal cord did not react with guinea pig liver and kidney. In addition, activity to spinal cord could be removed from sera by absorption with spinal cord but not with kidney or liver.
Analysis of lymphocyte proteins from New Zealand black mice by two-dimensional gel electrophoresis.
Authors: Lal R B , Monos D S , Chused T M , Cooper H L
Published: December 2022

Splenic lymphocyte proteins from New Zealand Black (NZB) mice, which spontaneously develop autoimmune disease, and several control strains were analyzed by two-dimensional polyacrylamide gel electrophoresis. A number of strain- and age-related differences were observed, among which was the persistently elevated synthesis of two peptides, 12.5 KD and 10.5 KD, by spleen cells from older NZB mice. Although synthesis of these peptides was moderately high in young NZB and control mice, it diminished with age in control mice. These proteins were found in the cytoplasm and were not expressed on the plasma membrane nor secreted into the medium. Production of these proteins was restricted to B and null cells; T cells did not synthesize these peptides. These proteins appear to be indicators of disease activity, because their increased synthesis was associated with lymphocyte subset alterations associated with the onset of overt autoimmune disease in NZB mice.
Murine interstitial nephritis. III. The selection of phenotypic (Lyt and L3T4) and idiotypic (RE-Id) T cell preferences by genes in Igh-1 and H-2K characterizes the cell-mediated potential for disease expression: susceptible mice provide a unique effector T cell repertoire in response to tubular antigen.
Authors: Neilson E G , McCafferty E , Mann R , Michaud L , Clayman M
Published: December 2022

The effector T cell repertoire in experimental interstitial nephritis was examined in a variety of susceptible and nonsusceptible mice. We observed that L3T4+ effector T cells in disease-susceptible mice disappear soon after immunization in preference to the emergence of Lyt-2+ effector cells. These latter cells respond with delayed-type hypersensitivity to tubular antigen in the context of H-2K. Such cells also express idiotypes (RE-Id) shared with kidney-bound alpha TBM-Ab that are regulated by an interactional effect of genes in Igh-1 and H-2K. These Lyt-2+ effector cells can be removed from renal infiltrates, and the transfer of similar cells under the renal capsule of naive mice results, within 5 days, in local interstitial nephritis. Nonsusceptible mice, however, not having these immune response genes, produce either L3T4+, Lyt-1+, RE-Id- effector T cells, which only respond to tubular antigen in the context of I-A, or Lyt-2+, RE-Id- T cells, which may lack very fine specificity. These findings suggest that susceptible mice carry a unique set of immune response genes that promote a T cell selection process that operates after induction, during the differentiation and development of disease-producing effector T cells.
Activated human B cells display a functional IL 2 receptor.
Authors: Mittler R , Rao P , Olini G , Westberg E , Newman W , Hoffmann M , Goldstein G
Published: December 2022

These studies deal with the expression of a functional IL 2 receptor on activated primary human B cells. Antibody against the receptor (alpha-TAC) reacted with 25 to 65% activated B cells, inhibited B cell proliferation by 50% and inhibited B cell secretion of Ig by greater than 90%. These effects were shown to be independent of contaminating T lymphocytes. Anti-TAC immunoprecipitated a molecule of identical size (65,000 daltons) from T and B lymphocytes; B cells were also shown to actively synthesize the IL 2 receptor. The chymotryptic peptide chromatograms of TAC antigen from T and B cells show these molecules to be indistinguishable.
Interleukin 2-mediated induction of lytic activity in a cloned murine CTL line.
Authors: Howe R C , Milstone D S , Ratliff T L , Russell J H
Published: December 2022

We have analyzed the ability of interleukin 2 (IL 2) to induce lytic activity within a cloned murine H-2Dd-specific CTL line. Weakly lytic CTL harvested 6 to 7 days after previous stimulation with irradiated DBA/2J spleen cells and conditioned medium from secondary MLC (MLC SN) could be reactivated to high antigen-specific lytic activity with highly purified gibbon IL 2 or E. coli-produced human recombinant DNA IL 2. Dose-response curves with IL 2 and MLC SN suggest that IL 2 may be the principal detectable activity in MLC SN that is active on these CTL. Doses of IL 2 or MLC SN that were saturating for the induction of lytic activity were suboptimal for the expression of DNA synthesis measured by 3HTdR incorporation. This is consistent with a mechanism in which different threshold IL 2 concentrations are required to induce these two biologic responses. Finally, we show that IFN-gamma has little effect on the expression of lytic activity either alone or in combination with IL 2 in this bioassay.
Human epidermal cells and squamous carcinoma cells synthesize a cytokine that augments natural killer cell activity.
Authors: Luger T A , Uchida A , Köck A , Colot M , Micksche M
Published: December 2022

Normal as well as transformed epidermal cells (EC) have recently been reported to produce a cytokine--EC-derived thymocyte-activating factor (ETAF), which according to its biologic as well as biochemical properties is indistinguishable from macrophage-derived interleukin 1 (IL 1). In the present study, the effect of supernatants (SN) derived from normal EC and a human squamous carcinoma cell (SCC) line were tested for their effects on natural killer (NK) cell activity. EC- as well as SCC-derived SN were able to augment in vitro NK cell activity of peripheral blood lymphocytes against K 562 cells. In contrast, adherent cell-derived, IL 1-containing SN did not affect NK cell activity. Upon high-pressure liquid chromatography (HPLC) gel filtration, ETAF and the EC-derived NK cell activity-augmenting factor (ENKAF) exhibited a similar m.w. However, by using reverse-phase HPLC, ETAF and ENKAF eluted as distinct peaks of activity, indicating that SCC cell-derived ENKAF is different from ETAF. Furthermore, ENKAF does not contain interleukin 2 (IL 2) or interferon (IFN) activity. The enhancement of NK cell activity was dose dependent and evident after 20 hr of preincubation of effector cells. Pretreatment of target cells with ENKAF did not affect the susceptibility of the target cells. The NK activity of large granular lymphocytes (LGL) purified by discontinuous Percoll gradient centrifugation and further depleted of high-affinity sheep erythrocyte rosetting cells was enhanced by ENKAF. In contrast, no NK cell activity was expressed by LGL-depleted T cell populations before or after treatment with ENKAF. In a single cell cytotoxicity assay in agarose, the number of lymphocyte binding to K 562 was not affected by ENKAF, but the frequency of dead conjugated target cells and presumably of active killer cells was increased by pretreatment with ENKAF. Additional incubation of LGL with ETAF did not further increase ENKAF-mediated augmentation of NK activity. In contrast to ETAF, ENKAF was not chemotactic for polymorphonuclear leukocytes. These results indicate that normal as well as transformed EC release a unique cytokine--ENKAF--which augments NK cell activity of LGL but is distinct from ETAF, IL 2, and IFN.
IgA isotype-restricted idiotypes associated with T15 Id+ PC antibodies.
Authors: Nishinarita S , Claflin J L , Lieberman R
Published: December 2022

Idiotypes are believed to be due to the structural conformation of the variable region of immunoglobulins (Ig). We have found an idiotype (C3-24) that requires both variable and constant regions of the heavy chain to be expressed. C3-24 Id is associated with both the T15 variable region from anti-phosphorylcholine (PC) antibodies and the constant region for the alpha-heavy chain. High titer anti-PC serum from a variety of inbred strains of different Ig haplotypes failed to express C3-24 Id. However, when IgA but not IgG or IgM fractions were isolated from a pool of anti-PC serum from BALB/c mice, more than 70% of the molecules expressed C3-24 Id. The high frequency of the expression of C3-24 Id in IgA anti-PC hybridoma proteins from mice of different Ig haplotypes and in the IgA fraction of normal anti-PC antibodies from BALB/c and presumably other strains of mice suggests that idiotypic determinants produced by the three-dimensional product of VH and CH regions may not be unusual.
gamma-Interferon enhances the secretion of arachidonic acid metabolites from murine peritoneal macrophages stimulated with phorbol diesters.
Authors: Hamilton T A , Rigsbee J E , Scott W A , Adams D O
Published: December 2022

Macrophage activation in vivo has been associated with qualitative and quantitative alterations in the release and metabolism of arachidonic acid. In the present study, we examined the effect of in vitro macrophage activation with recombinant gamma-interferon (IFN-gamma) on arachidonic acid secretion induced by exposure to a variety of stimulating agents. Secretion stimulated by challenge with unopsonized zymosan, insoluble immune complexes, the calcium ionophore A23187, or combinations thereof was unaltered in IFN-gamma-treated macrophages. However, when phorbol diesters active as tumor promoters were employed as challenge agents, arachidonate secretion was enhanced as much as 10-fold over that seen in nonactivated controls. The enhanced secretory response to PMA was detectable as early as 1 hr after exposure to IFN-gamma, reached a maximum within 3 to 6 hr, and subsequently declined to control levels even in the continued presence of the agent. Treatment with IFN-gamma did not alter the pattern of individual metabolites produced by macrophages challenged with either zymosan or PMA. Finally, the sensitivity to phorbol diesters was also increased by treatment with IFN-gamma (ED50 reduced from 35 ng/ml to 4 ng/ml). Thus, IFN-gamma could prime macrophages for a substantially amplified response to phorbol esters. Because the cellular mediator of PMA action has been identified as a Ca++, phospholipid-dependent protein kinase, a role for this enzyme in macrophage functional development is indicated.
In vitro antigen-specific antibody response to the species-specific surface protein antigens of typhus group rickettsiae by human peripheral blood mononuclear cells: generation of an antigen-dependent suppressor T cell.
Authors: Misiti J , Dasch G A
Published: December 2022

We defined conditions suitable for in vitro synthesis of rickettsia-specific antibody by human PBMC cultured with the SPA of Rickettsia typhi or R. prowazekii and without addition of mitogens or polyclonal stimulators. Antibody synthesis, as measured by an enzyme-linked immunosorbent assay, was cycloheximide-inhibitable and antigen-specific. PBMC from individuals with prior rickettsial infection made antibody, whereas PBMC from those receiving vaccine or with undetectable levels of serum anti-SPA antibody did not. Antibody production was T helper cell-dependent because isolated B cells did not generate antigen-specific antibody in the absence of autologous T cells. Furthermore, prior exposure of T cells to high concentrations of SPA led to the generation of an antigen-dependent population of cells capable of suppressing the anti-SPA response when co-cultured with autologous PBMC and optimal SPA concentrations. This system should serve as an effective tool for analyzing the cellular interactions involved in the in vitro regulation of antigen-specific antibody synthesis by human PBMC.
Synthetic Fc peptide-mediated regulation of the immune response. II. Analysis of secreted immunoglobulin classes, accessory cell contribution, and lymphocyte proliferation in p23-stimulated spleen cell cultures.
Authors: Hobbs M V , Morgan E L , Weigle W O
Published: December 2022

The synthetic peptide p23 representing residues 335 to 357 in the CH3 domain of human IgG1 was able to increase levels of secreted Ig in murine spleen cell cultures. This in vitro response was optimal in the presence of between 10(-4) and 10(-3) micron p23/ml and the levels of secreted Ig reached a maximum on day 4 or day 5 of culture. Supernatants from p23-treated cell cultures generally contained more IgM than IgG and undetectable levels of IgA. Induction of Ig secretion by p23 was macrophage-independent but T cell-dependent and, with respect to the latter case, removal of T cells from spleen cells reduced the levels of both IgM and IgG. Although maintaining the B cell differentiation-inducing quality of its progenitor molecule, the Fc gamma fragment, p23 appeared to have lost the ability to induce B cell proliferation. Evidence is presented that a sequence functionally similar to p23 is extant in mouse IgG by showing that murine Fc gamma fragments were also able to induce increases in Ig-secreting cells in murine spleen cell cultures.
Control of B cell proliferation: inhibition of responses to B cell mitogens induced by plasma cell tumors.
Authors: Berman J E , Zolla-Pazner S
Published: December 2022

A multitude of factors has been described that positively and negatively regulate B cell proliferation. A model system for the study of negative control of B cell function is provided by mice bearing plasmacytomas (PC-mice). In PC-mice, the primary immune response, as measured by development of antibody-forming cells (AFC), is severely suppressed. The present report specifically identifies a block in B cell proliferation as the apparent cause of this reduction in AFC production. Thus, the proliferative response of B cells from the spleens of PC-mice (PC-spleens) was significantly impaired when stimulated with four different B cell mitogens (lipopolysaccharide, Salmonella typhimurium mitogen, anti-mu conjugated to Sepharose, and 8-mercaptoguanosine). Nevertheless, the mitogen-responsiveness of these B cells was recovered when they were segregated by various methods from macrophages. These data suggest that the proliferative ability of the B cells in PC-spleens is inherently normal. In concordance with this conclusion, it was shown that suppressor cells from PC-spleens can block the proliferation of normal B cells derived from nontumor-bearing mice. This inhibition does not require direct cell contact and is mediated via soluble factors. The relevance of these results to previous studies of PC-induced immunosuppression and to the control of normal B cell proliferation is discussed.
Site-selective homing of antigen-primed lymphocyte populations can play a crucial role in the efferent limb of cell-mediated immune responses in vivo.
Authors: Spangrude G J , Araneo B A , Daynes R A
Published: December 2022

Lymphoid cells of the mammalian immune system exhibit special migratory properties within their in vivo environment. This fundamental characteristic is important to the protection of the organism from infection and neoplastic transformation by a process termed immunologic surveillance. The importance of lymphocyte recirculation was addressed by investigating the role of site-selective homing of lymphocytes during the efferent phase of an in vivo adoptively transferred immune response. We approached this problem by using pertussis toxin (PT), a known inhibitor of lymphoid cell migration in vivo. PT is a protein secreted by the bacterium Bordetella pertussis, which induces a selective and long-lasting inhibition of the emigration of lymphocytes from the bloodstream into solid tissue. In this study, we demonstrate that the blockade of lymphocyte extravasation potential mediates inhibition of certain cell-mediated immune responses in vivo. We investigated the effect of PT on the extravasation of antigen-primed lymphocytes into solid tissue. The results show that the loss of lymphocyte homing potential after in vitro treatment of the primed cells with PT is accompanied by an inhibition of antigen-specific contact hypersensitivity after adoptive transfer. This result suggests that the process of lymphocyte extravasation into nonlymphoid tissue sites such as the skin shares fundamental similarities to the selective localization of circulating lymphocytes to lymph nodes. Furthermore, the inhibition of contact hypersensitivity observed after the i.v. adoptive transfer of PT-treated antigen-primed cells could be circumvented by transferring the PT-treated cells directly into a tissue site with the relevant antigen. In contrast, no inhibition in the number of antibody-forming cells present within the spleen was observed after an adoptive transfer of PT-treated sheep red blood cell-primed lymphocytes, a result that is in agreement with radiotracer data. Thus, the inhibitory effect of PT on the adoptive transfer of contact hypersensitivity was established to be a direct result of the PT-mediated alteration of cellular migration, because PT inhibits the entrance of lymphocytes into specific tissue sites without inhibiting other cellular functions. This conclusion is additionally supported by experiments that showed that lymphocytes that have been pretreated with PT exhibit normal in vitro responses, as assayed by mitogenesis in response to concanavalin A and by the differentiation and function of alloantigen stimulated or hapten-specific cytotoxic T lymphocytes.(ABSTRACT TRUNCATED AT 400 WORDS)
Antigen processing requirements for T cell activation: differential requirements for presentation of soluble conventional antigen vs cell surface MHC determinants.
Authors: Finnegan A , Needleman B W , Hodes R J
Published: December 2022

The present studies were undertaken to characterize the antigen-processing requirements involved in the responses to T cells to soluble antigen (antigen specific), to allogeneic cell surface MHC determinants (alloreactive), and to syngeneic MHC determinants (autoreactive). T cell clones were used that have dual cross-reactive specificities either 1) for self MHC plus soluble antigen and for allogeneic MHC products or 2) for syngeneic MHC and for allogeneic MHC, in order to permit comparison of the processing requirements for responses of the same T cell to distinct antigenic stimuli. The proliferative responses of antigen-specific, Ia-restricted T cell clones to soluble antigens were sensitive to treatment of antigen-presenting cells (APC) with 125 to 250 microM chloroquine, a lysosomotropic agent previously shown to inhibit the processing of soluble antigens. In contrast, the same T cell clones were only minimally affected in their ability to respond to similarly chloroquine-treated APC expressing allogeneic MHC products. The responses of autoreactive T cell clones to syngeneic stimulating cells and their cross-reactive responses to allogeneic cells were both resistant to chloroquine treatment of stimulating cells. The failure of chloroquine to inhibit antigen presentation to autoreactive T cell clones suggests that these clones are specific for self Ia not associated with in vitro processed foreign antigen. Thus, chloroquine sensitivity distinguishes the in vitro antigen-processing requirements for presentation of the soluble antigens tested from the requirements for presentation of syngeneic or allogeneic cell surface MHC determinants to the same T cells.
Susceptibility of cytotoxic T lymphocyte (CTL) clones to inhibition by anti-T3 and anti-T4 (but not anti-LFA-1) monoclonal antibodies varies with the "avidity" of CTL-target interaction.
Authors: Shaw S , Goldstein G , Springer T A , Biddison W E
Published: December 2022

To explore the role of the T3, T4, and LFA-1 molecules in high and low "avidity" interactions between SB2-specific cytotoxic T lymphocyte (CTL) clones and their targets, monoclonal antibody-mediated inhibition of cytotoxicity has been studied in experiments that vary the "avidity" of interaction in three different ways. 1) Previous results have been extended with respect to different CTL clones assayed on the same SB2-positive target cells. Differences between clones in susceptibility to anti-T3 inhibition paralleled variations in anti-T4 inhibition, and both correlated inversely with the "avidity" of the effector-target interaction (inferred previously from studies of conjugate dissociation). 2) A high "avidity" clone, 8.4, was identified that lysed not only SB2-positive cells but also cross-reacted on a few SB2-negative cells. Cold target inhibition studies confirmed the cross-reaction, and together with conjugate dissociation studies, indicated that cross-reaction to be of lower "avidity" than the specific recognition of SB2. Cross-reactive lysis was much more susceptible to inhibition by anti-T3 and anti-T4 than was specific lysis. 3) Anti-T3 and anti-T4 blocking was analyzed in the presence of anti-Ia antibody to reduce the amount of Ia antigen available on the target. Anti-T3 and anti-T4 antibody blocking was more efficient after the addition of anti-Ia antibody concentrations that (by themselves) produced minimal inhibition of lysis. As a control, anti-LFA-1 antibody blocking was analyzed in each of these three experimental systems that compare interactions of different "avidity"; minimal variation was observed in the efficiency of inhibition by anti-LFA-1. Thus, anti-T3 and anti-T4 inhibition correlates inversely with the "avidity" of that CTL-target interaction, but anti-LFA-1 inhibition does not.
Prolactin receptors on human T and B lymphocytes: antagonism of prolactin binding by cyclosporine.
Authors: Russell D H , Kibler R , Matrisian L , Larson D F , Poulos B , Magun B E
Published: December 2022

Prolactin (PRL) receptors have been identified recently on human peripheral blood mononuclear cells (MNC) and may be involved in the regulation of cell-mediated immunity. Cyclosporine (CsA), an immunosuppressive cyclic endecapeptide utilized to prolong graft survival in human organ transplant patients, affects PRL binding to MNC. At concentrations of CsA from 10(-10) through 10(-8) M, the amount of PRL bound to MNC markedly increased to ca. 400% of controls, whereas CsA concentrations of 10(-6) and 10(-5) M totally inhibited PRL binding to lymphocytes. The ability of low concentrations of CsA to enhance PRL binding was temperature-dependent and did not occur when binding assays were conducted at 4 degrees C. PRL displaced [3H]CsA from lymphocytes with ca. 50% displacement at 10(-9) M PRL and total displacement at concentrations of 10(-7), 10(-6), and 10(-5) M. Growth hormone did not displace [3H]CsA in similar experiments. CsA also did not alter the binding of a beta-receptor antagonist to MNC, again suggesting that CsA was specific in its antagonism of PRL binding. A CsA analog with no immunosuppressive action, cyclosporin H, did not alter PRL binding to MNC. Furthermore, PRL receptors were demonstrated on four cell lines of human and mouse origin. Finally, PRL receptors were identified on purified populations of T and B lymphocytes isolated from human spleens, and CsA again inhibited PRL binding at concentrations of 10(-7) and 10(-6) M. The presence of PRL receptors on T and B lymphocytes suggests that PRL may be involved in the regulation of humoral and cell-mediated immunity, and that one effect of CsA on immune function may be its ability to inhibit the effects of PRL action on these lymphocytes.
Immunochemical and genetic studies of Amb.t. V (Ra5G), an Ra5 homologue from giant ragweed pollen.
Authors: Roebber M , Klapper D G , Goodfriend L , Bias W B , Hsu S H , Marsh D G
Published: December 2022

Giant ragweed pollen allergen Amb.t. V (Ra5G), a homologue of short ragweed pollen Amb.a. V (Ra5S), was isolated in ultrapure form from a 16-min extract of ragweed pollen by a combination of molecular sieving through an Amicon hollow fiber cartridge (H1P5), cation-exchange chromatography, and gel filtration. The size was found to be 4400 daltons (D) by amino acid analysis and 6000 D by SDS-PAGE, and the pI was 8.3 as determined by isoelectric focusing. There was no cross-reactivity detected between the two Amb. V antigens by immunodiffusion and IEP with the use of hyperimmune antisera raised against crude or highly purified antigens. Cross-reactivity between the two Amb. V antigens was further investigated by inhibition double antibody radioimmunoassay by using the sera of nine selected ragweed-allergic patients who had recently been immunized with either mixed short-giant ragweed pollen extract or with short ragweed extract alone and who had IgG antibodies (Ab) to Amb.t. V and generally to Amb.a. V. Unlabeled Amb.t. V did not inhibit the binding of 125I-Amb.a. V to the IgG Ab in any of the sera tested. Conversely, unlabeled Amb.a. V produced some inhibition of the binding of 125I-Amb.t. V to the patients' IgG Ab, primarily in those patients who had received immunotherapy with short ragweed alone. This weak cross-reactivity was probably a result of the primary structural homology between the two protein allergens. The sera from two groups of ragweed-allergic individuals were investigated for the presence of IgG and IgE Ab to Amb.t. V. The presence of IgG Ab was found to be associated both with previous (or current) immunotherapy with giant ragweed extract and with HLA-Dw2. The HLA association is of interest in view of the previously established association between Dw2 and response toward the homologue Amb.a. V. The result suggests the existence of a similar genetic control at the primary level of antigenic recognition of the two Amb. V antigens.
Production of interleukin 3 and gamma-interferon by an antigen-specific mouse suppressor T cell clone.
Authors: Koyasu S , Nakauchi H , Kitamura K , Yonehara S , Okumura K , Tada T , Yahara I
Published: December 2022

An interleukin 2 (IL 2)-dependent, keyhole limpet hemocyanin (KLH)-specific, mouse suppressor T cell clone, 3D10, was found to produce interleukin 3 (IL 3) and gamma-interferon (IFN-gamma) in response to T cell mitogens Con A and PHA. Different from KLH-specific suppressor factor (TsF) that was spontaneously released into the medium when cultured in IL 2-containing conditioned medium, the production of IL 3 and IFN-gamma was induced by mitogenic stimuli. IL 3, IFN-gamma, and TsF were separable by gel filtration through a Sephadex G-100 column, being recovered in fractions of m.w. 25,000 to 30,000, 45,000 to 50,000 and 60,000 to 70,000, respectively. On the other hand, minimum size of IL 3 and IFN-gamma were shown to be about 25,000 and 20,000, respectively, by determining the lymphokine activities contained in the extracts from slices of SDS gels. These results indicate that IFN-gamma was present as a homodimer or hetero-complex with another carrier protein(s), whereas IL 3 was present as a monomeric form. A highly positive correlation (a correlation coefficient r = 0.96) between the titers of IL 3 and IFN-gamma produced by seven subclones derived from 3D10 was obtained, suggesting that IL 3 and IFN-gamma are induced by a process with a common mechanism. 3D10 also produced IL 3 and IFN-gamma when cultured with its specific antigen, KLH, in the presence of antigen-presenting cells. When Con A-stimulated 3D10 cells were labeled with L-[35S]methionine, we found that at least three proteins, with m.w. of 35,000, 25,000, and 20,000, were specifically released into medium by the stimulation. The latter two may be IL 3 and IFN-gamma described above, respectively, because of the similarities in m.w.
The molecular basis of the requirement for antigen processing of pigeon cytochrome c prior to T cell activation.
Authors: Kovac Z , Schwartz R H
Published: December 2022

Antigen-induced activation of T lymphocytes that co-recognize Ia molecules has been shown to require an antigen-processing step by the presenting cell before T cell stimulation can occur. In this report, we demonstrate that antigen presentation of pigeon cytochrome c to an E kappa beta:E kappa alpha-restricted T cell hybridoma, 2C2, is inhibited by pretreatment of the antigen-presenting cells (APC) either with chloroquine or with fixation by paraformaldehyde. The chloroquine effect was partially reversible after 22 hr; the paraformaldehyde effect was not. In contrast, these treatments had little or no effect on the presentation of the carboxy-terminal cyanogen bromide cleavage fragment of pigeon cytochrome c, residues 81 to 104. There was at least a 50-fold greater potency of the fragment, as compared to that of the intact molecule, when paraformaldehyde-fixed APC were used. In addition, the fixed cells did not present synthetic fragments of the cytochrome c that were nonstimulatory when presented by unfixed cells. This observation showed that the loss of potency, demonstrated previously for analogs of pigeon cytochrome c with single amino acid substitutions at positions such as 99, was not a consequence of an alteration in the rate of antigen-processing. This result is consistent with our earlier hypothesis that these residues are contact amino acids with the antigen-specific T cell receptor or the Ia molecule. The major goal of these experiments was to define the molecular transition that occurred as a result of antigen processing. To achieve this end, we tested a variety of pigeon cytochrome c molecules and fragments for their ability to be presented by paraformaldehyde-fixed APC. Apocytochrome c, the denatured form of the molecule with the heme removed, could not be presented by the fixed cells, nor could the fragment 60-104, derived by acid cleavage of the tryptophan at position 59. Both molecules stimulated an IL 2 response from the T cell hybridoma when unfixed APC were utilized, demonstrating that the conditions used to prepare these two molecules did not destroy their antigenic determinant. In contrast, carboxy-terminal fragments, both native and synthetic, ranging in size from 16 to 39 amino acids, were capable of stimulating in the presence of paraformaldehyde-fixed APC. In particular, the partial-digest cyanogen bromide fragment, residues 66 to 104, was only twofold less potent than the pigeon fragment 81-104.(ABSTRACT TRUNCATED AT 400 WORDS)
Studies of leukotriene B4-specific binding and function in rat polymorphonuclear leukocytes: absence of a chemotactic response.
Authors: Kreisle R A , Parker C W , Griffin G L , Senior R M , Stenson W F
Published: December 2022

Rat PMN isolated from peripheral blood show a small amount of high-affinity (specific) binding of [3H]-LTB4 at nanomolar concentrations. This binding is reversible and has a stereospecificity similar to rat PMN aggregation in response to several LTB4 analogs. This population of binding sites shares many characteristics with a population of high-affinity binding sites in human PMN; however, human PMN bind a significantly greater amount of [3H]-LTB4 to a second population of specific binding sites that is not present in rat PMN. The aggregation responses of human and rat peripheral blood PMN to LTB4 are similar in magnitude and specificity, but unlike human PMN, LTB4 fails to elicit a chemotactic response in rat PMN at concentrations from 10(-10) M to 10(-6) M. Rat PMN also fail to metabolize exogenous LTB4 when compared with human PMN. These data suggest that different PMN functions, such as chemotaxis and aggregation, may involve different classes of specific receptors. The finding that rat PMN do not exhibit chemotaxis to LTB4 calls for a reevaluation of the relevance to inflammation in humans of studies of inflammation performed in rat models.