bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for an intracellular pool of a migration inhibitory factor-associated, activation antigen of human mononuclear phagocytes, Mo3e.
Authors: Todd R F , Adams M D , Rogers C E , Tripp L R , Liu D Y
Published: December 2022

Mo3e is a protease-sensitive Ag (p75,50) selectively expressed by human monocytic cells stimulated in vitro by exposure to various activating factors including PMA. Here, we report the existence of a large intracellular pool of Mo3e Ag in addition to that expressed on the surface of activated U-937 cells. As detected by quantitative immunofluorescence analysis, permeabilization of unstimulated and PMA-stimulated U-937 cells revealed a latent pool of Mo3e Ag that was 75-fold and 9-fold greater, respectively, than the magnitude of Mo3e Ag expressed on the surface. PMA stimulation not only induced an increase in the relative proportion of Mo3e antigen expressed on the surface membrane, but also stimulated a 1.8-fold increase in "total" Mo3e detectable in permeabilized cells. Trypsin treatment of intact PMA-stimulated U-937 cells eliminated surface Mo3e expression but had little measureable effect on the total Mo3e pool. Permeabilization also uncovered a sequestered compartment of Mo3e Ag in I-937 cells, a variant of U-937 that is surface Mo3e negative. Although the PMA-induced surface Mo3e expression of U-937 was abrogated by cycloheximide, the total pool of Mo3e detectable in permeabilized PMA-stimulated cells was only partially reduced; cycloheximide treatment caused no reduction in the intracellular Mo3e compartment of unstimulated U-937 cells. Detergent lysates of PMA-stimulated U-937 cells exhibited undiminished quantities (relative to untrypsinized cells) of p75 and p50 proteins immunoreactive with anti-Mo3e mAb as detected by Western blotting. This trypsin-sequestered intracellular Mo3e Ag may serve as a reservoir for the up-regulated surface expression of Mo3e that occurs as a result of mononuclear phagocyte activation.
Characterization of a promonocyte clone chronically infected with HIV and inducible by 13-phorbol-12-myristate acetate.
Authors: Folks T M , Justement J , Kinter A , Schnittman S , Orenstein J , Poli G , Fauci A S
Published: December 2022

The present study has investigated the effect of PMA, an inducer of monocyte differentiation, on HIV expression in a chronically infected promonocyte clone. After acute HIV infection of U937 cells, clones that constitutively expressed varying levels of HIV were isolated by limiting dilution. One clone (U1) produced low levels of HIV but was found to increase its production 20-fold after PMA induction, as detected by reverse transcriptase or A capture. Further characterization of U1 indicated that PMA could induce cellular differentiation and maturation in the clone similar to that in uninfected U937 cells. In addition, functional studies revealed that superoxide anion production from the U1 clone was not different from that of uninfected U937 cells. Electron microscopic studies of U1 indicated that PMA induced endocytotic vesicles containing many HIV particles. These studies provide a model at the clonal level to 1) examine latency or chronicity of HIV infection in monocytes and 2) delineate the signals required for conversion to high level viral expression.
Evolution of B cell lineage lymphomas in mice with a retrovirus-induced immunodeficiency syndrome, MAIDS.
Authors: Klinken S P , Fredrickson T N , Hartley J W , Yetter R A , Morse H C
Published: December 2022

Mice infected with LP-BM5 murine leukemia virus develop lymphadenopathy, splenomegaly, hypergammaglobulinemia, and profound immunosuppression associated with enhanced susceptibility to infection. In this study, molecular genetic analyses of spleen and lymph node cells from infected mice showed the early course of disease was associated with polyclonal proliferations of both B and T cells but that by 12 wk oligoclonal expansions of B or T cells could be detected. When near death, the mice were killed and almost all exhibited clonally restricted populations of B cells, and continuous cultures of B lineage cells were established from three of 19 mice. Histologically, lymph nodes with polyclonal lymphoproliferative lesions were indistinguishable from nodes with clonally restricted populations of cells. However, aggressive immunoblastic lymphomas of characteristic morphology were seen in nonlymphoid organs, particularly in the brain. The demonstration of terminal B cell lymphomas in murine AIDS extends the similarities between this syndrome and AIDS in humans.
Sequences of the VH and VL regions of murine monoclonal antibodies against 3-fucosyllactosamine.
Authors: Kimura H , Cook R , Meek K , Umeda M , Ball E , Capra J D , Marcus D M
Published: December 2022

Many mAb that bind the carbohydrate antigenic determinant 3-fucosyl-lactosamine (3-FL), Gal beta 1-4[Fuc alpha-3]GlcNAc-R have been raised in BALB/c mice, and we are studying the structure and regulation of these antibodies. In this report, we present the first information about their amino acid sequences and the Ig gene segments used to encode them. V regions of the H and L chains of three anti-3-FL antibodies, PMN6, PMN29, and PM81, were sequenced by a combination of mRNA and amino acid sequencing. The L chain sequences of PMN6 and PM81 antibodies indicate that their VK and JK regions are encoded by VK24B and JK1 germ-line genes, respectively. The nucleotide and amino acid sequences of the H chains suggest that the three anti-3-FL antibodies are encoded by the VH441 gene segment of the X24 VH family, and this conclusion was supported by Southern filter hybridization with VH441 and JH3-JH4 probes. PMN29 has at least 11 amino acid substitutions, which is an unusually large amount of somatic mutation for an IgM antibody. Previous analyses of BALB/c genomic libraries with VHX24 and VH441 probes make it unlikely that this VH family contains additional germ-line genes, but this possibility cannot be excluded. All three antibodies use the DQ52 and JH4 gene segments. The single VH and VL gene segments used to encode the anti-3-FL antibodies is in contrast to the multiple VH and VL segments used by antibodies against other carbohydrate Ag such as alpha 1-6 dextran and group A streptococcal carbohydrate. VH441 also encodes the VH regions of antibodies against galactan and levan (beta 2-6 fructosan). The similarities among VH segments of antibodies against 3-FL, levan, and galactan, and the striking differences in their CDR3 sequences, suggest that CDR3 plays an important role in the formation of the Ag binding site. The use of a single VH segment from the smallest VH gene family by antibodies against at least three different carbohydrate determinants is noteworthy. It raises the possibility that the amino acid sequence encoded by VH441 has some general structural features that make it particularly well adapted for binding to carbohydrate sequences.
Protein Rou. A human IgA hybrid.
Authors: Mihaesco E , Gendron M C , Congy N , Frangione B
Published: December 2022

Protein Rou is a human IgA2 myeloma protein that carries the isoallotype marker n A2m(2). Partial amino acid sequence of its H chain (alpha) shows that the hinge region and the CH2 domain are homologous to alpha 2-chain and the CH1 and the CH3 domains homologous to alpha 1. Moreover, the CH1 domain contains the H-L disulfide bond identical to alpha 1. It is concluded that Rou H chain is a hybrid molecule caused by a recombination between alpha 1 and alpha 2 genes. The recombination event occurred between alpha 1-exon 1 and alpha 2-exon hinge and corresponds to position 222-223 of the alpha-chain.
Cytochalasin stimulates phosphoinositide metabolism in murine B lymphocytes.
Authors: van Haelst C , Rothstein T L
Published: December 2022

The ability of cytochalasin to alter phosphoinositide metabolism was evaluated in naive, murine splenic B lymphocytes. The generation of total inositol phosphates was stimulated by treatment with cytochalasin D, as was the generation of inositol trisphosphate. The cytochalasin-induced increase in inositol phosphates appeared to depend on interaction with actin, and it was inhibited by phorbol esters. Inositol phosphate production was not stimulated in splenic T lymphocytes. The results suggest that the previously observed increase in intracellular calcium produced by cytochalasin is part of a more generalized signaling event that includes phosphoinositide turnover, and, further, raise the possibility of a functional association between actin and phospholipase C.
Cell surface expression and alloantigenic function of a human class I MHC heavy chain gene (HLA-B7) in transgenic mice.
Authors: Chamberlain J W , Nolan J A , Gromkowski S H , Kelley K A , Eisenstadt J M , Herrup K , Janeway C A , Weissman S M
Published: December 2022

We have introduced the gene encoding the heavy chain of the human MHC class I Ag HLA-B7 into transgenic mice. The gene was shown to be expressed at both the RNA and protein level. Cell surface HLA-B7 was detected on whole spleen cells by immunoprecipitation and on purified T cells by flow cytometry (FACS). Normal mice immunized with H-2-syngeneic B7-transgenic spleen cells generated CTL capable of killing transgenic cells and B7-expressing human JY cells. Anti-HLA mAb blocked the killing of JY cells. These results indicate that the human class I Ag HLA-B7 can be expressed at the surface of transgenic spleen cells in the absence of human beta 2-microglobulin, and that a significant fraction exists in a form recognizable by nontransgenic CTL as a major histocompatibility Ag unrestricted by H-2.
CD3/Ti gamma A: a functional gamma-receptor complex expressed on human peripheral lymphocytes.
Authors: Faure F , Jitsukawa S , Triebel F , Hercend T
Published: December 2022

We have recently developed a mAb designated anti-Ti gamma A, which was found to immunoprecipitate from the well characterized CD3+ TCR alpha/beta- F6C7 fetal clone a CD3-associated disulfide-linked gamma-glycoprotein. This antibody recognizes approximately 3% of adult peripheral lymphocytes and delineates a CD2+ CD3+ TCR alpha/beta- CD4- NKH1- subset where expression of CD8 appears to vary widely from one individual to another. In the present study, we have used anti-Ti gamma A mAb to assess whether gamma-chains expressed on these adult lymphocytes are used as functional R. The two activities which have been associated thus far with TCR gamma+ cells, that is, IL-2-dependent proliferation and non-MHC-restricted cytotoxicity, were investigated here by using either resting or activated Ti gamma A+ lymphocytes. On the resting state, these cells (which appear as a very homogeneous population of granular lymphocytes) mediate little if any NK activity that could not be augmented by anti-Ti gamma A mAb. In contrast, after initial stimulation by PHA plus rIL-2 and subsequent culture in the presence of IL-2, activated Ti gamma A+ lymphocytes were strongly lytic against a series of conventional NK target cell lines. This cytotoxic function was either blocked or enhanced by anti-Ti gamma A mAb, depending upon experimental conditions. With respect to proliferation, it was possible to induce responses of resting Ti gamma A+ lymphocytes with antibody-coated CNBr beads only in the presence of exogenous IL-2, whereas, in culture, the same cells proliferated directly and secreted IL-2 after treatment by anti-Ti gamma A beads. Taken together, these data demonstrate that a major subset of circulating CD3+ TCR alpha/beta- lymphocytes use protein products of T cell gamma rearranging genes as functional R structures.
Isotype-specific immunoregulation. Systemic antigen induces splenic T contrasuppressor cells which support IgM and IgG subclass but not IgA responses.
Authors: Kitamura K , Kiyono H , Fujihashi K , Eldrige J H , Beagley K W , McGhee J R
Published: December 2022

In the present study, we have isolated and characterized the Lyt-1+, -2- T contrasuppressor (Tcs) cells from mice systemically primed with SRBC. Adoptive transfer of splenic Tcs cells from these mice abrogates oral tolerance and supports IgM and IgG anti-SRBC plaque-forming cell (PFC) responses; however, unlike the responses seen after transfer of Tcs cells derived from orally primed mice, low IgA responses were seen. Mice systemically primed with lower SRBC doses (0.01 to 1%) exhibited contrasuppression only within the L3T4- T cell subset, whereas mice primed with a high dose of SRBC (10%), harbored Lyt-1+, -2- Tcs cells in both the L3T4+ and L3T4- subsets. Both the L3T4- and L3T4+ Tcs cell subsets supported IgM and IgG responses when adoptively transferred to orally tolerized mice, and when added to tolerized spleen cell cultures. Splenic Tcs cells from systemically primed mice supported mainly IgG1 and IgG2b subclass anti-SRBC PFC responses, a pattern also seen with Tcs cells derived from orally primed mice. Both L3T4+ and L3T4- Tcs cells from systemically primed mice exhibited well established characteristics of contrasuppressor cells including binding to Vicia villosa lectin and expression of I-J. The splenic effector Tcs cells which support IgM, IgG1 and IgG2b anti-SRBC PFC responses are antigen-specific, since both L3T4- and L3T4+ Tcs cells from spleens of mice primed with 10% SRBC reverse tolerance to SRBC, but not to horse erythrocytes (HRBC). Further, both L3T4- and L3T4+ Tcs cells from HRBC-primed mice reverse tolerance to IgM and IgG anti-HRBC, but not to anti-SRBC responses. Isolation of T3-positive Lyt-1+, -2- and L3T4- Tcs cell subsets by flow cytometry followed by adoptive transfer, showed that effector Tcs cells express T3 and presumably contain an Ag-R (TCR-T3 complex). These studies show that systemic priming with heterologous RBC induces splenic Ag specific Tcs cells in a dose-dependent manner, which support IgM and IgG subclass responses, but not IgA responses.
Characterization of antigen processing and presentation by resting B lymphocytes.
Authors: Gosselin E J , Tony H P , Parker D C
Published: December 2022

The production of antibody to a thymus-dependent Ag requires cooperation between the B cell and an Ag-specific Th cell. MHC restriction of this interaction implies that the Th cell recognizes Ag on the B cell surface in the context of MHC molecules and that the Ag-specific B cell gets help by acting as an APC for the Th cell. However, a number of studies have suggested that normal resting B cells are ineffective as APC, implying that the B cell must leave the resting state before it can interact specifically with a Th cell. Other studies, including our own with rabbit globulin-specific mouse T cell lines and hybridomas, show that certain T cell lines can be efficiently stimulated by normal resting B cells. One possible explanation for the above contradiction is that our B cells have become activated before presentation. Here we show that presentation by size-selected small B cells is not the result of nonspecific activation signals generated by the T cells or components of the medium. Also, although LPS activation does increase the efficiency of presentation by small B cells, use of large cells in place of small cells or preincubation of resting B cells with mitogenic doses of anti-Ig does not. Another possibility that we considered was that small B cells are unable to process Ag and that we had selected T cell lines that were capable of recognizing native Ag on the B cell surface. In the majority of cases, experiments with B cell lines and macrophages have shown that Ag presentation requires Ag processing, a sequence of events that includes internalization of Ag into an acid compartment, denaturation or digestion of Ag into fragments, and its return to the cell surface in the context of class II MHC molecules. The experiments reported here show that our T cell lines require an Ag processing step and that small resting B cells, like other APC, process Ag before presenting it to T cells. Specifically, we show that an incubation of 2 to 4 h is required after the Ag pulse before Ag presentation becomes resistant to irradiation. Shortly after the pulse, the Ag enters a pronase-resistant compartment. Although efficient Ag presentation requires initial binding to membrane Ig, Ag is no longer associated with membrane Ig at the time of presentation and is not presented in its intact form, because removal of membrane Ig by goat anti-Ig blocks presentation before but not after the Ag pulse.
Resting B lymphocytes can be triggered directly through the CDw40 (Bp50) antigen. A comparison with IL-4-mediated signaling.
Authors: Gordon J , Millsum M J , Guy G R , Ledbetter J A
Published: December 2022

Resting tonsillar B lymphocytes were shown to enlarge and become more buoyant when exposed to either IL-4 or a mAb (G28-5) to the 50-kDa CDw40 Ag. A striking feature of activation through CDw40 was the promotion of strong homotypic adhesions which did not occur in populations cultured with IL-4. Whereas the CDw40 antibody down-regulated its target Ag, an increased expression of CDw40 accompanied IL-4 stimulation. Similarly, only IL-4, and not the CDw40 antibody, was able to induce the appearance of CD23 on the resting B cell surface. Functionally, the major consequence of ligating CDw40 on resting B cells was that they remained alert to subsequent mitogenic signaling--cells incubated with IL-4 developed the same sluggish response as noted in control cultures. Together, IL-4 and the CDw40 antibody provoked a small, but significant, level of DNA synthesis in tonsillar B cells which was enhanced dramatically by the inclusion of low m.w. B cell growth factor. This latter agent had no discernible direct effect on resting B lymphocytes. The different pathways which have been observed for triggering resting B cells are discussed.
Potentiation of lymphokine-induced macrophage activation by tumor necrosis factor-alpha.
Authors: Heidenreich S , Weyers M , Gong J H , Sprenger H , Nain M , Gemsa D
Published: December 2022

In this study, we examined the possible role of TNF-alpha and lymphotoxin (TNF-beta) as cofactors of macrophage activation. The results demonstrate that both TNF were capable of enhancing the cytostatic and cytolytic activity of murine peritoneal macrophages against Eb lymphoma cells. The potentiation of tumor cytotoxicity became apparent when macrophages from DBA/2 mice were suboptimally activated by either a T cell clone-derived macrophage-activating factor or by IFN-gamma plus LPS. Neither TNF-alpha nor TNF-beta could induce tumor cytotoxicity in IFN-gamma-primed macrophages, indicating that TNF cannot replace LPS as a triggering signal of activation. In LPS-resistant C3H/HeJ macrophages, which were unresponsive to IFN-gamma plus LPS, a supplementation with TNF fully restored activation to tumor cytotoxicity. Furthermore, TNF-alpha potentiated a variety of other functions in low-level activated macrophages such as a lactate production and release of cytotoxic factors. At the same time, TNF-alpha produced a further down-regulation of pinocytosis, tumor cell binding and RNA synthesis observed in activated macrophages. These data demonstrate new activities for both TNF-alpha and TNF-beta as helper factors that facilitate macrophage activation. In particular, the macrophage product TNF-alpha may serve as an autocrine signal to potentiate those macrophage functions that were insufficiently activated by lymphokines.
A 34-amino acid peptide of the third component of complement mediates properdin binding.
Authors: Daoudaki M E , Becherer J D , Lambris J D
Published: December 2022

In this study, a peptide of 34 amino acids from the Mr 40,000 C terminus alpha-chain fragment of C3 was found to mediate properdin (P) binding. Treatment of the Mr 40,000 fragment with CNBr generated one major Mr 17,000 fragment that was capable of binding P. Amino acid sequence data placed the Mr 17,000 fragment within residues 1385 to 1540 of the C3 sequence. After analyzing this sequence for highly conserved segments within the C3 from other species (which bind P) and segments of low similarity within human C4, mouse C5, and alpha 2-macroglobulin (which do not bind P), a 34-amino acid (1402 to 1435) peptide was synthesized. This synthetic peptide bound to P and inhibited its binding to C3b. In addition, it exhibited negative regulatory activity on the alternative pathway as it inhibited the lysis of rabbit erythrocytes by normal human serum. These results show that the P-binding site is located within the residues 1402 to 1435 of the C3 sequence.
Synthesis and release of platelet-activating factor by stimulated human mononuclear phagocytes.
Authors: Elstad M R , Prescott S M , McIntyre T M , Zimmerman G A
Published: December 2022

Platelet-activating factor (PAF) is a potent phospholipid mediator that may participate in inflammatory responses by virtue of its ability to activate platelets, leukocytes, and vascular cells. We examined the synthesis and release of PAF by human peripheral blood monocytes (PBM) isolated by countercurrent elutriation. PAF was produced after stimulation by calcium ionophore A23187 (IoA), opsonized zymosan (OpsZ), and PMA with a relative order of potency IoA much greater than OpsZ greater than PMA. The portion of PAF subsequently released from the cell was dependent on the specific agonist, the time of incubation, and the presence of albumin. Under optimal conditions, PBM released 67, 49 and 32% of the total PAF produced in response to IoA, OpsZ, and PMA, respectively. Changes in PAF metabolism were observed in PBM that were examined after short term adherence or differentiation into macrophages. Adherent PBM accumulated and released less PAF than suspended monocytes, and monocyte-derived macrophages produced less PAF than the parent PBM. The ability of monocytes to release significant amounts of newly synthesized PAF from the cell is unusual among human cell types, which in general retain the vast majority of the lipid, and may be of particular pathophysiologic importance.
Graft-versus-host reaction-induced immune modulation. I. Donor-recipient genetic disparity and the differential expression of Lyt-2, L3T4, and Ly-6 during acute reactions in the host thymus.
Authors: Levy R B , Cotterell A H , Jones M , Malek T R
Published: December 2022

To investigate the effects of graft-vs-host reactions (GvHR) on cells in a central lymphoid compartment, GvHR were induced across class I/II or class II only major histocompatibility complex differences utilizing the parent into nonirradiated F1 hybrid (P----F1) model. Thymocytes were subsequently examined during the acute stage of GvHR for the expression of Lyt-2, L3T4, and Ly-6 cell surface molecules. Class I/II "suppressive" GvHR resulted in a dramatic decrease (greater than 85%) in total thymocyte numbers by 2 wk after parental cell injection. Although a dramatic decrease in the percentages of Lyt-2 (85%----30%) and L3T4 (95%----50%) expression was observed, the percentage of thymocytes expressing Ly-6 was markedly increased compared to uninjected controls (5%----greater than 80%). This increased percentage was not due solely to a selective loss of Ly-6 negative cells from the thymus, since the actual number of Ly-6 positive cells was greater in GvHR mice than in controls. Class II GvHR during the same time interval resulted in a less dramatic decrease (20 to 60%) in total thymocyte numbers. In addition, the effect on the percentages of Lyt-2 (85%----approximately 70%) and L3T4 (95%----approximately 85) expression was subtle and transient. However, intrathymic Ly-6 expression was again clearly enhanced (5%----20 to 30%). Class I/II "proliferative" or "stimulatory" GvHR differ from "suppressive" reactions in that they are characterized by stimulatory pathologic symptoms and the appearance of autoimmune abnormalities. Such GvHR were found to result in minimal alteration of total thymocyte numbers. Similarly, the percentage expression of Lyt-2 and L3T4 was marginally affected. However, the percentage of Ly-6 expression was increased from 5%----20 to 30% and thus these intrathymic lymphocyte profiles more closely resemble those of class II as compared to class I/II "suppressive" GvHR. The present findings therefore demonstrate that major histocompatibility complex differences alone do not necessarily determine the effects of GvHR on recipient thymocytes and that Ly-6 is a useful marker for the early detection of GvHR-associated immunologic events.
Differential regulatory signals delivered by antibody binding to the CD28 (Tp44) molecule during the activation of human T lymphocytes.
Authors: Damle N K , Doyle L V , Grosmaire L S , Ledbetter J A
Published: December 2022

Molecule CD28 (Tp44) is expressed on the surface of majority of human T cells and has been implicated to play an active role in the regulation of T cell growth. The present study examines the effect of antibody binding to the CD28 molecule during T cell activation. Anti-CD28 but not isotype-matched anti-CD5 mAb consistently augmented anti-CD3-induced and IL-2-induced T cell proliferation and subsequent release of soluble CD25 molecule. When added together, mAb anti-CD28 and anti-CD5 acted synergistically to cause 2- to 7-fold enhancement of T cell activation induced by anti-CD3 mAb or IL-2 with no effect on the development of non-MHC-restricted IL-2-activated killer T cells. In contrast, alloantigen-induced T cell proliferation, soluble CD25 release, and the subsequent development of CTL were all inhibited by anti-CD28 mAb. Moreover, alloantigen-induced proliferative response of both CD4+ and CD8+ T cells was inhibited by anti-CD28 without affecting the cytolytic effect of CTL. Because valency of anti-CD28 binding has been implicated as an important factor in signal transduction, this was explored in the allogeneic MLR by using Fab and F(ab')2 fragments of anti-CD28 mAb and anti-mouse kappa mAb. The inhibitory effect of anti-CD28 mAb in the MLR was reversed by cross-linking of anti-CD28 mAb with anti-mouse kappa mAb. In addition, cross-linking of the CD28 molecule on alloactivated T lymphoblasts but not that on resting T cells with anti-CD28 and anti-mouse kappa induced their proliferation in the absence of the priming alloantigen. These results indicate that stimulatory or inhibitory signals delivered through the CD28 molecule are determined by the degree of cross-linking of this molecule. In addition, these results also suggest that Ag-induced CD3-TCR-mediated T cell responses are more dependent on signals delivered through the CD28 molecule than those induced with anti-CD3, and thus these results have implications for potential use of anti-CD28 in sustained propagation of Ag-specific T cells.
Role of the CD22 human B cell antigen in B cell triggering by anti-immunoglobulin.
Authors: Pezzutto A , Rabinovitch P S , Dörken B , Moldenhauer G , Clark E A
Published: December 2022

As B cells mature during ontogeny the CD22 human differentiation Ag is exported from the cytoplasm onto the membrane. Surface expression is lost in terminal differentiation and after activation. In tonsils, CD22 is expressed on the surface of 60 to 80% of the dense B cells. Some IgM+ dense cells, however, and buoyant in vivo activated B cells are CD22-. This differential expression of CD22 and the finding that an anti-CD22 mAb augmented anti-Ig induced B cell proliferation suggested that CD22 may play a role in B cell activation. In this study we have found that CD22+ but not CD22- B cells could be triggered by anti-IgM or anti-IgD to have increased free intracellular calcium ([Ca2+]i). The presence of CD22 rather than of IgD seems to determine the ability of B cells to respond to anti-Ig with a [Ca2+]i flux. Also the proliferative response to anti-Ig or anti-Ig + B cell growth factor was restricted to the CD22+ population. Anti-CD22 mAb, although not inducing [Ca2+]i on their own after binding to B cells, did augment [Ca2+]i fluxes by anti-Ig when cross-linked. Together these results suggest that CD22 may regulate triggering of B cells through surface Ig perhaps by acting as a "bridge" to transmit an early signal into the cytoplasm.
Endothelial activation during interleukin 2 immunotherapy. A possible mechanism for the vascular leak syndrome.
Authors: Cotran R S , Pober J S , Gimbrone M A , Springer T A , Wiebke E A , Gaspari A A , Rosenberg S A , Lotze M T
Published: December 2022

A major sequela of immunotherapy with interleukin 2 (IL-2) is development of a vascular leak syndrome. The pathogenesis of this toxic effect is not known. We have examined pre- and post-treatment skin biopsies from 14 patients undergoing systemic administration of IL-2 for evidence of endothelial cell activation. Specifically, we have used the immunoperoxidase technique to detect the expression of three different activation antigens: endothelial-leukocyte adhesion molecule 1, detected with monoclonal antibody H4/18; intercellular adhesion molecule 1, detected with antibody RR1/1; and histocompatibility leukocyte antigen-DQ, detected with antibody Leu 10. Each of these antigens may be induced on cultured endothelial cells by various cytokines (although not by IL-2) and is expressed during endothelial cell activation in vivo at sites of delayed hypersensitivity and other immune responses. Pretreatment biopsies from each patient showed no endothelial expression of endothelial-leukocyte adhesion molecule 1 and only weak to moderate expression of intercellular adhesion molecule 1 and histocompatibility leukocyte antigen-DQ (except for one specimen unreactive with Leu 10). After 5 days of treatment, every patient showed marked endothelial expression of all three antigens (except for the same patient who remained unreactive with Leu 10). Endothelial-leukocyte adhesion molecule-1 expression was confined to postcapillary venular endothelium whereas intercellular adhesion molecule-1 and Leu 10 also were expressed on stromal cells and mononuclear cells. Thus, we conclude that i.v. administration of IL-2 leads to endothelial cell activation. Because IL-2 fails to induce the same antigens on cultured endothelial cells, we infer that IL-2 acts in vivo by inducing the production of other cytokines (e.g., interleukin 1, tumor necrosis factor, lymphotoxin, and interferon-gamma). Finally, since endothelial cell activation at sites of cell-mediated immune responses is well known to result in vascular leakiness to macromolecules, we propose that the vascular leak syndrome accompanying IL-2 therapy may arise from widespread inappropriate endothelial cell activation.
Cell-mediated immune responses in human infection with Onchocerca volvulus.
Authors: Gallin M , Edmonds K , Ellner J J , Erttmann K D , White A T , Newland H S , Taylor H R , Greene B M
Published: December 2022

Mechanisms involved in modulation of the immune response in persons with chronic Onchocerca volvulus infection are poorly understood. In this study in vitro reactivity of PBMC to O. volvulus antigen (Ovag), streptolysin O (SL-O) and the mitogen PHA was tested in 62 infected individuals (INF), 17 persons living in the endemic area with exposure to the infection, but with no detectable infection (END), and 7 healthy controls (CTRL) in Liberia, West Africa. Mean blastogenic responses to Ovag were minimal and did not differ between the groups. There was, however, heterogenous reactivity to Ovag in the INF and END. For example, individuals with a history of therapy, and half of those less than 17 yr old who were tested, showed high responses. No significant differences in the response to SL-O or PHA were detected between the groups. IL-2 production in response to Ovag was minimal in the majority of infected subjects. Exogenous IL-2 was found to cause a significant increase in mean responses to Ovag and SL-O in INF and END only. Similarly, Ovag did not stimulate IL-1 production in most INF, whereas stimulation with LPS led to significantly greater production of IL-1. Depletion of plastic and nylon wool adherent cells did not increase responses to parasite-related antigen in INF, END or CTRL; however, responses to SL-O were augmented in INF, an effect that was also observed in CTRL. Finally, depletion of CD8 or CD16 cells in INF by C lysis did not increase blastogenic responses. These results indicate that cell-mediated immunity to parasite-related Ag as reflected in lymphocyte responses in vitro is diminished in infected individuals, and that this may be caused by defects in T cell activation.
Identification of the avian homologues of mammalian CD4 and CD8 antigens.
Authors: Chan M M , Chen C L , Ager L L , Cooper M D
Published: December 2022

Two mAb were produced against chicken T cells. The CT4 antibody precipitated a polypeptide of Mr 64,000 under both reducing and non-reducing conditions. The CT8 antibody precipitated a molecule of Mr 63,000 under non-reducing conditions and polypeptide chains of Mr 34,000 under reducing conditions, suggesting that the CT8 molecule is a disulfide-linked homodimer. Tissue distribution studies by immunofluorescence revealed that the CT4 and CT8 Ag were expressed by the majority of thymocytes and by subpopulations of CT3+ cells in peripheral tissues. The CT4 reactive molecule was found on approximately 70% of thymocytes, 10% splenocytes, and 45% of lymphoid cells in blood. The CT8 reactive molecule was expressed on approximately 80% of thymocytes, 50% of spleen cells, and 15% of blood lymphocytes. Two-color immunofluorescence indicated that the CT4 and CT8 Ag were expressed together on most thymocytes and on mutually exclusive subsets of cells in the spleen and blood. Ontogenic studies revealed a sharp increase in the frequencies of CT4+ and CT8+ cells in the thymus between days 13 and 16 embryonic life. Both CT4 and CT8 antibodies inhibited PHA- and Con A-induced proliferative responses of splenocytes, and the degree of inhibition correlated with the frequencies of CT4+ and CT8+ lymphoblasts. Treatment of spleen cells with CT4 antibody and inhibited PWM-induced IL-2 production, and removal of CT8+ cells inhibited the cytolytic activity induced by allogeneic lymphocyte stimulation. Macrophages did not express detectable CT4 reactivity. These results suggest that the CD4 and CD8 molecules and their tissue-restricted patterns of expression are highly conserved in birds and mammals.
The expression of B cell surface receptors. I. The ontogeny and distribution of the murine B cell IgE Fc receptor.
Authors: Waldschmidt T J , Conrad D H , Lynch R G
Published: December 2022

The ontogenic appearance and lymphoid tissue distribution of the murine B cell IgE FcR (Fc epsilon R) was examined. Flow cytometry was utilized to study the expression of the Fc epsilon R on splenic B cells from mice of increasing age, as well as B cells from various lymphoid organs. A large panel of B cell tumors was also screened for the presence of the Fc epsilon R. The results demonstrate that the Fc epsilon R appears very late in B cell development, and is preceded in appearance even by IgD. In adult animals, the Fc epsilon R was found to be expressed on virtually all mature IgM, IgD bearing B cells, whether taken from the spleen, lymph nodes, or Peyer's patches. Further examination showed that B cells which had switched to express an isotype other than IgD, appeared to no longer display the Fc epsilon R. When surveying a variety of B cell tumors, the Fc epsilon R was found to be present on WEHI 279, an IgM, IgD-bearing lymphoma. The receptor was not found on pre-B cell, immature B cell, switched B cell, or secreting B cell tumors. Taken together, these results indicate that the B cell Fc epsilon R is expressed predominantly on mature, virgin B cells, and is lost after activation and switching.
Glial retinal Müller cells produce IL-1 activity and have a dual effect on autoimmune T helper lymphocytes. Antigen presentation manifested after removal of suppressive activity.
Authors: Roberge F G , Caspi R R , Nussenblatt R B
Published: December 2022

The Müller cell is the major glial element of the mammalian retina. It can be induced to express MHC class II determinants in culture, when exposed to supernatant from activated lymphocytes. In an in vitro co-culture system, Müller cells had been shown to exert a profound inhibitory influence on Ag- and IL-2-driven proliferation of Th cell lines. In the present report we demonstrate that Müller cells can produce IL-1 activity, and that in conditions where their inhibitory action is suppressed, they display the capacity to efficiently function as APC. Mildly trypsinized and glutaraldehyde-fixed Müller cells that had been preincubated with Ag and IFN-gamma-containing rat spleen conditioned medium were able to present Ag to an S-Ag specific Th lymphocyte line, which has the capacity to induce a severe uveoretinitis in rats. Addition of the Ag after fixation did not result in presentation, showing that Müller cells had to process the nominal Ag into an immunogenic form. It was also found that the efficiency of presentation was greatly increased in the presence of naive syngeneic or allogeneic accessory cells. This enhancing effect could not be reproduced with rIL-1. This report extends our ongoing study of interactions between the retinal glial Müller cell and T lymphocytes. The results show that these interactions can be diverse, even opposite in different conditions, and suggest the possibility that Müller cells could play a determining role in the course of immune reactions at the level of the neuro-retina.
The 2H4 (CD45R) antigen is selectively decreased in multiple sclerosis lesions.
Authors: Sobel R A , Hafler D A , Castro E E , Morimoto C , Weiner H L
Published: December 2022

To analyze expression of the 2H4 (CD45R) Ag on inflammatory cells in the central nervous system immune response, immunohistochemical staining with a panel of anti-T cell mAb was performed on central nervous system tissues from 12 patients with multiple sclerosis (MS) and 8 patients with viral encephalitis. Only rare cells were stained with anti-2H4 in MS plaques, plaque edges, and adjacent white matter, whereas 2H4+ cells were more numerous in viral encephalitis (p less than 0.001). By contrast, no quantitative differences were found between MS plaque edges and viral encephalitis with anti-4B4 (helper-inducer function associated), anti-CD4, anti-CD3, and anti-IL-2R mAb, although there were fewer CD8+ cells in MS (p less than 0.01). These data indicate that the 2H4 Ag is selectively decreased and, because it is associated with suppressor-inducer function of CD4+ cells, that there may be a defect in the down-regulation of the in situ immune response in MS.
The expression and modulation of IL-1 alpha in murine keratinocytes.
Authors: Ansel J C , Luger T A , Lowry D , Perry P , Roop D R , Mountz J D
Published: December 2022

Murine and human keratinocytes produce an IL-1-like factor that appears to be similar if not identical to monocyte-derived IL-1. IL-1 may be an important mediator in cutaneous inflammatory responses, however, little is currently known concerning factors that may modulate IL-1 expression in keratinocytes. To address this issue we examined the effect of LPS, UV, and the cell differentiation state on murine keratinocyte IL-1 mRNA expression. Our results indicated that as with the murine P388D1 monocyte cell line, PAM 212 keratinocytes constitutively express abundant amounts of IL-1 alpha mRNA. On exposure to LPS (100 micrograms/ml) for 8 h there was more than 10 times the increase in PAM 212 IL-1 alpha mRNA which was accompanied by a sixfold increase in supernatant IL-1 activity. Similarly UV irradiation had a significant effect on keratinocyte IL-1 alpha expression. High dose UV (300 mJ/cm2) inhibited PAM 212 IL-1 alpha expression at 4, 8, 24, 48 h post-UV whereas a lower dose of UV (100 mJ/cm2) inhibited UV at 4 and 8 h post-UV, but induced IL-1 expression at 24 and 48 h post-UV. The expression of IL-1 alpha varied with the differentiation state of the keratinocytes. Freshly removed newborn murine keratinocytes were found to constitutively express IL-1 alpha mRNA. Keratinocytes grown in low [Ca2+] tissue culture media (0.05 mM) for 6 days, functionally and phenotypically become undifferentiated and express increased quantities of IL-1 alpha mRNA, whereas cells grown in high [Ca2+] media (1.2 mM) for 6 days become terminally differentiated and IL-1 expression ceased. Keratinocytes cultured for 3 days in low [Ca2+] conditions expressed an intermediate level of IL-1 alpha. In contrast, little or no IL-1 beta mRNA was detected in either the PAM 212 cells or newborn murine keratinocytes. Thus LPS, UV, and cell differentiation state have a significant effect on expression of IL-1 alpha in murine keratinocytes.
IFN-gamma plus glucocorticoids stimulate the expression of a newly identified human mononuclear phagocyte-specific antigen.
Authors: Morganelli P M , Guyre P M
Published: December 2022

Glucocorticoid hormones, although able to exert profound immunosuppressive effects, do not suppress mononuclear phagocyte activation by IFN-gamma and may even enhance it. For example, expression and functional activity of the high affinity FcR for IgG on human mononuclear phagocytes (FcR gamma I) is increased by IFN-gamma and is maximal after co-treatment with IFN-gamma plus the glucocorticoid dexamethasone (DEX). To determine whether there are other mononuclear phagocyte surface Ag that are regulated in this manner, hybridomas were prepared using IFN-gamma-plus-DEX-treated human monocytes as immunogen. Five IgG1 mAb (Mac 2-8, 2-38, 2-48, 2-49, and 2-158) were developed that recognize a trypsin-sensitive mononuclear phagocyte-specific surface Ag of Mr 155,000. There was no detectable reactivity of these mAb to lymphocytes or granulocytes or to several cell lines, including U-937 and HL-60. The p155 Ag was detected on monocytes and increased significantly with time of culture or after treatment with DEX. Expression was maximal after co-treatment with rIFN-gamma plus DEX, but was inhibited or unaffected by treatment with IFN-gamma alone. For freshly isolated cells, expression of the p155 Ag was highest on peritoneal macrophages. Our results indicate that the p155 Ag is a newly identified Ag of the human mononuclear phagocyte lineage and may represent, in the least, a phenotypic marker of monocyte differentiation or maturation.
Role of leukotrienes in vascular changes in the rat mesentery and skin in anaphylaxis.
Authors: Leng W , Kuo C G , Qureshi R , Jakschik B A
Published: December 2022

The role of leukotrienes and other mediators of vascular changes in anaphylaxis were studied in rats sensitized with monoclonal anti-DNP IgE and challenged with DNP-BSA. Microvascular changes in the mesentery were followed by intravital fluorescent microscopy and in the skin by exudation of Evans blue dye. Administration of Ag i.v. caused a marked increase in the peristaltic movement of the intestine, plasma exudation, and arteriolar constriction in the mesentery. The microvascular changes were accompanied by a profound fall in blood pressure, which was biphasic. The first phase lasted for approximately 2 min. The second phase was very prolonged and the hypotension was still maintained 40 min after Ag challenge. The changes observed were dose dependent with regard to Ag. Intradermal application of Ag resulted in dose-dependent extravasation of Evans blue dye in the skin. Plasma exudation was partially inhibited by pyrilamine and methysergide. However, their effect seemed to be more pronounced in the skin than in the mesentery. The leukotriene D4-R antagonist L-649,923 and the 5-lipoxygenase inhibitor ONO-LP-049, alone or in combination with other inhibitors, did not alter the plasma leakage in the skin. In the mesentery, the leukotriene antagonists alone had a moderate effect on vascular permeability. However, the combination of these agents with pyrilamine completely inhibited macromolecular extravasation. The hypotension was modulated by the antihistamines as well as the leukotriene and serotonin antagonists. Pyrilamine inhibited the first phase and the second phase. The major effect of methysergide was a decrease in the duration of the hypotension. This was especially evident when it was administered in combination with other inhibitors. The leukotriene antagonists when given alone had moderate effects on the blood pressure changes. However, in combination with pyrilamine, the hypotension was substantially reduced. Leukotrienes appeared to be important mediators of the vascular changes in the mesentery but not in the skin (passive cutaneous anaphylaxis). They markedly potentiated the action of histamines.
Identification of platelet-activating factor receptors in P388D1 murine macrophages.
Authors: Valone F H
Published: December 2022

Platelet-activating factor (PAF) binding and metabolism by eight murine and human cell lines was analyzed. Only the murine P388D1 macrophage line had specific, high affinity PAF binding sites. PAF binding reached saturation within 10 min at room temperature and was irreversible. Minimal PAF metabolism was observed at the time binding saturation was achieved. Scatchard analysis of PAF binding revealed a single class of PAF receptors (7872 +/- 1310/cell) which had a dissociation constant of 0.08 +/- 0.01 nM (mean +/- SEM, eta = 6). The dissociation constant was confirmed independently by quantifying the kinetics of initial specific PAF binding. PAF binding was stereospecific, required an sn-2 acetyl substituent, and was inhibited by structurally diverse PAF antagonists including kadsurenone, BN 52021, triazolam, and CV3988. The fact that the receptors are functionally active was shown by the observation that 1 to 100 pM PAF increased free intracellular calcium in P388D1 cells in a dose-related manner. These studies demonstrate that P388D1 macrophages have functional PAF receptors whose affinity and structural specificities are similar to PAF receptors in other cells. The availability of a stable cell line that binds but does not metabolize PAF will greatly facilitate studies of the PAF receptor.
Generation of therapeutic T lymphocytes from tumor-bearing mice by in vitro sensitization. Culture requirements and characterization of immunologic specificity.
Authors: Chou T , Chang A E , Shu S Y
Published: December 2022

We have previously established an in vitro sensitization (IVS) procedure with which lymphocytes from tumor-bearing mice could be expanded and sensitized to acquire antitumor reactivity capable of mediating the regression of established pulmonary metastases from the weakly immunogenic MCA 105 murine sarcoma. Culture conditions required for the optimal generation of therapeutic effector cells were evaluated in the current study. Generation of effector cells by IVS required stimulation by intact tumor cells. Tumor cells killed by heat or disrupted by sonication were ineffective, but the antigenicity of tumor cells was not affected by gamma-irradiation. Long term established tumor cell lines could also serve as antigenic stimulator cells albeit with lower efficiency than fresh tumor cells. IL-2 was essential for cellular proliferation during IVS. The concentration of 1000 U/ml of IL-2 also induced nonspecific lymphokine-activated killer (LAK) activity. However, cytotoxic cells were generated during IVS in response to a broad range of IL-2 concentrations. At low IL-2 concentrations (2 to 10 U/ml), IVS cells were generated which displayed little or no LAK activity, had a greater therapeutic efficacy than those generated with high concentrations of IL-2 (100 to 1000 U/ml). Despite having high LAK activity, IVS cells, from cultures where IL-2 was added 3 or more days after initiation, had no therapeutic effect. Thus, the generation of therapeutic cells occurred independently of LAK cell production. Adoptive immunotherapy with IVS cells from MCA 105 tumor-bearing mice demonstrated cross-reactivity with the immunologically distinct MCA 106 but not the nonimmunogenic MCA 102 tumor. In contrast, IVS cells from MCA 106 tumor-bearing mice exhibited specific in vivo reactivity. In vitro cytotoxicity analyses revealed that IVS cells from MCA 105 and MCA 106 tumor-bearing mice were able to lyse both MCA 105 and MCA 106 target cells, but the reactivity toward inoculating tumors was highest. Considering previous findings that the MCA 105 and MCA 106 sarcomas possessed distinct tumor-specific transplantation Ag, the cross-reactivity observed in this study suggests that the immune response during progressive tumor growth may be different from that elicited in response to active immunization.