bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of anti-idiotypic suppressor T cells (Tsid) induced after antigen priming.
Authors: Sherr D H , Dorf M E
Published: December 2022

The induction and fine specificity of idiotype-specific suppressor T cells (Tsid) were studied. Spleen cells from C57BL/6 mice, immunized 4 wk previously with NP-KLH, failed to express NPb3 idiotype-bearing PFC when challenged in vitro with NP-Ficoll or NP-Brucella abortus. After treatment of NP-primed responder cultures with anti-Thy-1.2 anti-serum + C, NPb idiotype-bearing B cells could be detected. This B cell subset was preferentially suppressed by the addition of T cells from NP-primed mice. With this reconstitution protocol, it was determined that suppression of the NPb idiotype-bearing portion of the B cell response was mediated by a specifically induced T cell population (Tsid) that directly suppressed NPb-bearing B cells. As with a previously described suppressor population induced with hapten-modified syngeneic spleen cells (Ts2), the Tsid population bound and was lysed by NPb idiotype-bearing serum antibodies. However, the Tsid could be distinguished from the Ts2 population because it lacked I-J determinants and functioned as an effector T cell, not an intermediary suppressor cell. Furthermore, fine specificity studies with monoclonal NP-specific antibodies expressing various levels of serologically detectable NPb idiotypic determinants indicated that unlike the Ts2, the Tsid population reacts with conventional, serologically detected members of the NPb family. The combined idiotype binding studies for the Tsid and Ts2 populations demonstrate that the fine specificity of suppressor T cell populations reflects their independent mechanisms of regulation.
The allogeneic effect: the mechanism of allosuppression by Lyt-1, Ia- T cells.
Authors: Eastman A Y , Lawrence D A
Published: December 2022

The kinetics of allohelp mediated by diffusable factors revealed that help by nonirradiated T cells (TOR) peaked at 48 to 72 hr, followed by a sharp decline if the T cells remained in the cultures. The temporal decrease in help after 72 hr was not mediated by suppressor lymphokines because mixtures of early (24 to 48 hr) and late (120-hr) allogeneic supernatants enhanced help synergistically. Lyt-1, Ia- T cells mediated the temporal decline in help and suppressed allogeneic B cell activation in co-cultures, and this "down-regulatory" activity (allosuppression) was radiosensitive. Help by irradiated T cells (T1000R) increased gradually until it plateaued between 96 and 120 hr. The helper activities of the allogeneic supernatants were directly proportional to their T cell growth factor (TCGF) activities. In addition, their kinetics were identical, and the removal of TCGF from 48-hr allogeneic supernatants by adsorption with TCGF-dependent HT-2 cells depleted both helper and TCGF activities. Help was restored to depleted 48-hr and 120-hr allogeneic supernatants by preparations of TCGF obtained from concanavalin A (Con A)-stimulated FS6-14.13 hybridoma cells that were adsorbed with lipopolysaccharide (LPS)-activated B cells or normal spleen cells (NS), but not with HT-2 cells. These results indicate that allohelp is dependent on TCGF. Moreover, help was dependent on at least one factor in addition to TCGF, because a high level of synergy occurred between TCGF and the "help-deficient" 120-hr allogeneic supernatant. In conclusion, the mechanism whereby Lyt-1, Ia- T cells regulated B cell activation with positive and negative allogeneic effects was through the production and subsequent exhaustion of TCGF, respectively. The production of TCGF and help was radioresistant, but exhaustion of TCGF and suppression was radiosensitive.
Involvement of the transferrin receptor in the production and NK-induced suppression of human antibody synthesis.
Authors: Brieva J A , Stevens R H
Published: December 2022

Earlier studies have shown that the antibody-secreting lymphoblastoid (LB) B cells which arise in the circulation after immunization can be down-regulated by NK cells and an unusual T suppressor cell. Because the LB B cells require division in vitro before maximal antibody secretion, and as such may express the transferrin receptor, we wished to determine if this receptor is recognized by the NK and/or T suppressor cells. The addition of the antitransferrin receptor antibody B3/25 to cultures of LB cells resulted in a partial inhibition of antibody secretion. This inhibition was not seen with the addition of monoclonal anti-Dr or OKT-8 antisera, and indicated that the LB cells expressed the transferrin receptor and that its activity was required for antibody secretion. The addition of free Fe ions to the culture medium, however, allowed the secretion of antibody by the LB cells even in the presence of B3/25 antibody. Under these conditions, the inhibition of antibody secretion mediated by interferon-activated NK cells was no longer observed. The inhibition induced by pokeweed mitogen-stimulated T suppressor cells was not affected by the antibody treatment, suggesting that these two inhibitory cells recognize different target structures. These results indicate that LB B cells expressed the transferrin receptor at a stage of the in vitro culture, and that this structure is involved in the NK- but not the T cell-mediated inhibition of antibody synthesis.
Alterations in Fc receptor function of macrophages from streptozotocin-induced diabetic rats.
Authors: Abrass C K , Hori M
Published: December 2022

The presence of elevated levels of circulating immune complexes in diabetic humans and animals suggests impaired phagocyte function. To evaluate FcR-mediated phagocytosis, resident peritoneal macrophages were harvested from control, streptozotocin-induced diabetic, and insulin-treated diabetic rats. FcR number and avidity were determined from Scatchard analysis of binding of 125I-labeled aggregated rat IgG (ARG) to macrophages. The total and fractional catabolic capacity were determined by quantitating the digestion of ARG as a percent of the total ARG added and as a percent of ARG bound. Insulin-deficient diabetic rats had an increase in the number of FcR per cell (26.8 +/- 3.5 X 10(4)) as compared with control animals (13.1 +/- 1.2 X 10(4)) (p less than 0.01). In contrast, insulin-treated diabetic animals had a reduction in the number of FcR per cell (9.8 +/- 1.4 X 10(4)) (p less than 0.01). FcR of macrophages from insulin-deficient diabetic rats had a lower avidity (Kd = 6.9 +/- 1.8 X 10(-10)M) when compared with control (3.7 +/- 0.6 X 10(-10)M) and insulin-treated diabetic rats (3.6 +/- 0.9 X 10(-10)M) (p less than 0.01). Total catabolism of ARG by macrophages from both insulin-deficient and insulin-treated diabetic rats was reduced (31.0% +/- 3.4 and 17.5% +/- 3, respectively) when compared with controls (49.6% +/- 5.2) (p less than 0.01). Fractional catabolism by macrophages from insulin-deficient diabetic rats was significantly reduced (21% +/- 1.9 and 4.6% +/- 0.9/10(4) FcR) when compared with results from control rats (26% +/- 1.3 and 6.7% +/- 0.7/10(4) FcR) (p less than 0.01), whereas the results from insulin-treated diabetic rats (32% +/- 2.4 and 10.8% +/- 1.0/10(4) FcR) (p less than 0.01) were greater than those from controls. These studies demonstrate that FcR-mediated phagocytosis of soluble, "model" immune complexes is impaired in macrophages from both insulin-deficient and insulin-treated diabetic rats; however, different mechanisms account for this impairment in phagocytosis. Despite an increase in FcR number of macrophages from insulin-deficient diabetic rats, the depression of post-receptor-mediated catabolism results in a net depression in phagocytic activity. In contrast, macrophages from insulin-treated diabetic rats display augmented post-receptor-mediated catabolism; however, this does not overcome the low initial binding of ARG to the cell that results from the depression of FcR number.
Genetic studies in NZB mice. VI. Association of autoimmune traits in recombinant inbred lines.
Authors: Miller M L , Raveche E S , Laskin C A , Klinman D M , Steinberg A D
Published: December 2022

Because recombinant inbred lines, which are homozygous at most loci, can have any combination of parental genes, the numbers and the association of genes responsible for traits can be suggested by examining phenotypic distribution in these lines. Such studies, reported herein, uncovered two major families of nonlinked genetic loci whose interactions underlie autoimmune abnormalities in NZB mice. One family of genes leads to antibodies to murine leukemia virus, ssDNA, and erythrocytes, as well as to defective tolerance to bovine gamma-globulin. The other group of genes leads to polyclonal B cell activation, stem cell abnormalities, endogenous murine leukemia virus expression, and NTA. These studies help explain previously observed dissociations between the traits associated with these two groups of genes. Such genetic analyses provide the basis for future molecular biologic studies of the genes and gene products that underlie autoimmune disease.
Growth of a cloned helper T cell line induced by a monoclonal antibody specific for the antigen receptor: interleukin 1 is required for the expression of receptors for interleukin 2.
Authors: Kaye J , Gillis S , Mizel S B , Shevach E M , Malek T R , Dinarello C A , Lachman L B , Janeway C A
Published: December 2022

By using as an experimental system the induction of growth of a cloned, antigen:Ia-reactive helper T cell line by an antigen receptor-specific monoclonal antibody, we demonstrated that growth requires two essential co-factors, exogenously produced IL 1 and endogenously produced IL 2. The primary role of the IL 1 is in the expression of receptors on the T cell surface for IL 2, rather than for promoting the synthesis of IL 2. The use of a clone-specific activating monoclonal antibody at nanogram amounts to activate a cloned helper T cell should allow a detailed characterization of T cell activation via antigen receptor cross-linking.
Characterization of an antigen-specific suppressive factor derived from a cloned suppressor effector T cell line.
Authors: Kitamura K , Nakauchi H , Koyasu S , Yahara I , Okumura K , Tada T
Published: December 2022

A cloned effector-type suppressor T cell line, 3D10, which is known to suppress the antibody response against dinitrophenylated keyhole limpet hemocyanin (KLH), produced a soluble KLH-specific factor (TsF) that can replace the function of parental T cell clones. High activity of TsF was released spontaneously into the culture supernatant when cultured in interleukin 2 (IL 2)-containing medium, requiring no antigenic stimulation. The culture supernatant of 3D10 was also capable of inhibiting the KLH-induced proliferative response of primed T cells in an antigen-specific manner. The direct target of TsF was found to be Lyt-1+2- T cells undergoing an early stage of antigen-specific proliferation. TsF was antigen binding but lacked any other serologic markers such as I-J and immunoglobulin heavy chain-linked allotypic determinants on T cells. No genetic restriction was found in its action on allogeneic T cells. The production of IL 2 in proliferative T cells by antigenic stimulation was not inhibited by TsF. These results indicate that the TsF described here is the legitimate mediator produced by the effector-type suppressor T cell that suppresses the antigen-specific responses of Lyt-1+2- T cells. The m.w. of TsF was approximately 75,000.
Oxidized N-formylmethionyl-leucyl-phenylalanine: effect on the activation of human monocyte and neutrophil chemotaxis and superoxide production.
Authors: Harvath L , Aksamit R R
Published: December 2022

F-met-leu-phe, a potent neutrophil and monocyte chemoattractant, can be oxidized to F-met-leu-phe sulfoxide by metabolically activated neutrophils. We investigated the interaction of human neutrophils and monocytes with chemically prepared oxidized derivatives of F-met-leu-phe: F-met-leu-phe sulfoxide and F-met-leu-phe sulfone. We compared the derivatives with nonoxidized parent F-met-leu-phe for specific binding to neutrophils and monocytes, and for effectiveness as chemoattractants and stimuli of superoxide production. We observed that neutrophils did not migrate to either derivative over the concentration range of 10(-9) to 10(-3) M. In marked contrast, monocytes migrated to both oxidized peptides, with optimal chemotaxis occurring at derivative concentrations 10- to 100-fold higher than the optimal parent F-met-leu-phe concentration. F-met-leu-phe sulfoxide and sulfone stimulated neutrophil and monocyte superoxide production and specifically bound to both neutrophils and monocytes at optimal concentrations that were 10- to 100-fold greater than the optimal parent F-met-leu-phe concentration. These results suggest that the higher concentrations of oxidized derivatives required for monocyte migration and for neutrophil and monocyte superoxide production are due to a reduced affinity of the oxidized derivatives for the F-met-leu-phe receptor. The finding that oxidized F-met-leu-phe binds to the neutrophil receptor without eliciting a chemotactic response suggests that the F-met-leu-phe receptor complex or chemotaxis transduction mechanism is different in human neutrophils and monocytes.
Characterization of murine lymphocyte IgE receptors by flow microfluorometry.
Authors: Katona I M , Urban J F , Titus J A , Stephany D A , Segal D M , Finkelman F D
Published: December 2022

A flow microfluorometric technique has been developed to analyze IgE receptors on splenic and mesenteric lymph node mononuclear cells from BALB/c mice. Our data show that 1) the binding of DIBADL cross-linked IgE dimers to IgE receptors is specific in that it is inhibited by monomeric rat and mouse IgE but not by mouse or rabbit IgG or by the monoclonal anti-Fc gamma R antibody 2.4G2, and conversely, the binding of DIBADL cross-linked IgG dimers is inhibited by monomeric IgG or 2.4G2 but not by rat or mouse IgE; 2) the binding of IgE dimers is saturable on cells from uninfected and Nippostrongylus brasiliensis (Nb)-infected mice; 3) IgE dimer binding is detectable on most splenic B lymphocytes from uninfected and Nb-infected mice, but not on T lymphocytes from uninfected mice, and on few, if any, T lymphocytes from Nb-infected mice; 4) Nb infection causes a parallel increase in the percentages of B lymphocytes and cells expressing IgE receptors and Fc gamma R; 5) Nb infection leads to a marked increase in B lymphocyte IgE receptor expression, has little if any effect on IgE receptor affinity, and causes only minor changes in Fc gamma R expression; and 6) in vivo activation of B lymphocytes by a goat antibody to mouse IgD decreases IgE receptor expression considerably, but has a minimal effect on Fc gamma R expression. Thus, there are separate receptors for IgE and IgG on murine B lymphocytes, and the effect of Nb infection or anti-IgD treatment on their expression is different.
Heterologous antibody responses in mice with chronic T. cruzi infection: depressed T helper function restored with supernatants containing interleukin 2.
Authors: Reed S G , Inverso J A , Roters S B
Published: December 2022

Antibody production to sheep erythrocytes (SRBC) or hapten-conjugated SRBC (TNP-SRBC) was studied in mice with chronic Trypanosoma cruzi infections. Studies in vivo demonstrated that both IgM and IgG anti-SRBC responses were suppressed during chronic infection. Secondary IgG responses were suppressed regardless of whether the primary immunization was given before or after infection. The ability of cells from infected mice to provide help for antibody production was examined in vitro. Anti-SRBC responses were restored to cultures of whole spleen cells from infected mice by the addition of interleukin 2 (IL 2)-rich supernatants, indicating that these cells were capable of antibody production when sufficient help was provided. T cells from SRBC-primed infected mice were unable to provide significant help to normal B cell/M phi cultures for in vitro anti-TNP or anti-SRBC responses. The percentages of Thy-1+, Lyt-1+, and Lyt-2+ spleen cells were not significantly different between normal and infected mice. Anti-TNP and anti-SRBC responses were restored to cultures that contained T cells from infected mice and normal B cell/M phi by the addition of IL 2-rich spleen cell supernatants. The suppression of in vitro antibody responses in mice with chronic T. cruzi infections was associated with a lack of T cell help, which was provided by exogenous spleen cell supernatant.
Restoration of in vitro immune responses of spleen cells from mice infected with Trypanosoma cruzi by supernatants containing interleukin 2.
Authors: Tarleton R L , Kuhn R E
Published: December 2022

During the course of Trypanosoma cruzi infection, mice become suppressed in the ability to produce IL 2. Addition of supernatants from concanavalin A-stimulated normal spleen cells or supernatants from EL 4 cells enhanced the suppressed in vitro response of infected spleen cells to sheep erythrocytes. This enhancement was demonstrable at various times after infection and was shown not to be the result of Con A stimulation alone. Spleen cells from infected mice respond to IL 2-rich supernatants in Mishell-Dutton cultures in a dose-dependent fashion. Absorption of IL 2 activity from EL-4 supernatants by CTLL-2 cells results in a decrease in the enhancing effect of the supernatants on the in vitro antibody responses of infected spleen cells. Also, the reversal of suppression occurs only if IL 2-rich supernatants are added within 24 hr of the initiation of cultures. These results indicate that defective IL 2 production may play a role in the inability of mice infected with T. cruzi to respond appropriately to neoantigens.
Intracellular processing of membrane and secreted immunoglobulin delta-chains.
Authors: Argon Y , Milstein C
Published: December 2022

Membrane-bound and secreted immunoglobulin delta-chains are synthesized by the mouse hybridoma B1-8 delta.1 as two primary translation products (45,000 and 42,000, respectively) and are converted into three N-glycosylated forms. In addition to N-glycosylation, another modification, reflected in a size increase of 2000 to 3000, occurs within 8 min of synthesis and may be O-glycosylation. After these initial modifications, the N-linked carbohydrates of all three forms are partially trimmed, apparently in the endoplasmic reticulum. The secreted delta-chains acquire galactose and sialic acids less than 10 min before they are secreted. Monensin and CCCP, which are potent inhibitors of IgD secretion, inhibit the terminal glycosylation but not the other modifications of delta-chains. CCCP blocks the intracellular transport of IgD at an earlier stage of trimming than monensin. Within 10 min of the removal of CCCP, some of the accumulated IgD is terminally glycosylated and secreted. Membrane IgD is processed similarly to secreted IgD up to the stage blocked by CCCP. These observations suggest that final trimming and terminal glycosylation of IgD occurs in the Golgi complex, and that the other modifications occur in pre-Golgi compartments, where secreted IgD spends most of its transit time. We suggest that the rate-limiting step in the intracellular transport of both types of IgD is the passage from the ER to the Golgi complex.
Functional activity in vivo of effector T cell populations. II. Anti-tumor activity exhibited by syngeneic anti-MoMULV-specific cytolytic T cell clones.
Authors: Engers H D , Lahaye T , Sorenson G D , Glasebrook A L , Horvath C , Brunner K T
Published: December 2022

The functional activity in vivo of murine tumor-specific cytolytic T lymphocyte populations and clones was studied. Tumor cell destruction induced after the i.v. injection of cytolytic effector cells was quantitated by monitoring the elimination of 131IUdR-labeled tumor cells in the peritoneal cavity by using whole-body counting techniques. Mixed leukocyte-tumor cell cultures were established by using spleen cells from C57BL/6 regressor mice that had rejected an intramuscular tumor induced by the injection of MSV-MoMuLV virus. This effector cell population was observed to eliminate syngeneic MoMuLV-induced tumor cells in a dose-dependent manner. Treatment of the effector cell population with monoclonal anti-Lyt-2 antibodies plus complement totally abrogated their ability to induce tumor cell destruction in the peritoneal cavity. MSV-MoMuLV-specific Lyt-2+ cytolytic T cell clones derived by micro-manipulation of T lymphocyte-tumor cell conjugates were also tested for functional activity in vivo. Several clones induced a rapid, specific elimination of 131I-labeled MBL-2 tumor cells from the peritoneal cavity after i.v. injection, whereas others were inactive. Both active and inactive clones were highly cytolytic and secreted MAF/IFN-gamma lymphokines. In contrast to previous results obtained in a tumor allograft model, the MSV-MoMuLV-specific cytolytic T cell clones that were active in vivo did not proliferate in vitro in response to stimulation with irradiated tumor cells plus filler spleen cells in the absence of an added source of interleukin 2.
The role of tumor-specific Lyt-1+2- T cells in eradicating tumor cells in vivo. I. Lyt-1+2- T cells do not necessarily require recruitment of host's cytotoxic T cell precursors for implementation of in vivo immunity.
Authors: Fujiwara H , Fukuzawa M , Yoshioka T , Nakajima H , Hamaoka T
Published: December 2022

The present study determines the Ly phenotype of T cells mediating tumor cell rejection in vivo and investigates some of cellular mechanisms involved in the in vivo protective immunity. C3H/HeN mice were immunized to syngeneic X5563 plasmacytoma by intradermal (i.d.) inoculation of viable X5563 tumor cells, followed by the surgical resection of the tumor. Spleen cells from these immune mice were fractionated by treatment with anti-Lyt antibodies plus complement, and each Lyt subpopulation was tested for the reconstituting potential of in vivo protective immunity in syngeneic T cell-depleted mice (B cell mice). When C3H/HeN B cell mice were adoptively transferred with Lyt-1-2+ T cells from the above tumor-immunized mice, these B cell mice exhibited an appreciable cytotoxic T lymphocyte (CTL) response to the X5563 tumor, whereas they failed to resist the i.d. challenge of X5563 tumor cells. In contrast, the adoptive transfer of Lyt-1+2- anti-X5563 immune T cells into B cell mice produced complete protection against the subsequent tumor cell challenge. Although no CTL or antibody response against X5563 tumors was detected in the above tumor-resistant B cell mice, these mice were able to retain Lyt-1+2- T cell-mediated delayed-type hypersensitivity (DTH) responses to the X5563 tumor. These results indicate that Lyt-1+2- T cells depleted of the Lyt-2+ T cell subpopulation containing CTL or CTL precursors are effective in in vivo protective immunity, and that these Lyt-1+2- T cells implement their in vivo anti-tumor activity without inducing CTL or antibody responses. The mechanism(s) by which Lyt-1+2- T cells function in vivo for the implementation of tumor-specific immunity is discussed in the context of DTH responses to the tumor-associated antigens and its related Lyt-1+2- T cell-mediated lymphokine production.
1,25-Dihydroxyvitamin D3 inhibits antigen-induced T cell activation.
Authors: Bhalla A K , Amento E P , Serog B , Glimcher L H
Published: December 2022

The proliferative response of murine spleen and thymus cells to antigen but not to lectin was inhibited by the active metabolite of vitamin D3, 1,25-(OH)2D3. To directly examine the effect of 1,25-(OH)2D3 on T cell activation in the absence of other complicating interactions, we utilized a panel of cloned Ia-restricted T cell hybridomas that secrete IL 2 on activation by cloned Ia-bearing stimulator cells (TA3) or when stimulated by mitogen. Physiologic concentrations of 1,25-(OH)2D3 (0.01 to 0.1 nm) inhibited the antigen-induced secretion of IL 2 by several of these T cell hybridomas. This inhibition was dependent on the concentration of the free hormone and could be overcome by increasing the number of Ia-bearing stimulator cells used. Pretreatment of the T hybridoma but not the TA3 stimulator cell with 1,25-(OH)2D3 resulted in inhibition of activation. These results are consistent with the finding that specific 1,25-(OH)2D3 receptors are present on the T cell hybridomas but are lacking in TA3 cells. 1,25-(OH)2D3 failed, however, to inhibit the activation of the T cell hybridomas by lectin or by an anti-Thy-1 antibody. These findings suggest that 1,25-(OH)2D3 may be interfering with early events of antigen-induced T cell activation, perhaps by hindering T cell recognition of the relevant antigen on stimulator cell surfaces. This system should prove useful in studying the molecular mechanisms by which 1,25-(OH)2D3 acts to inhibit T cell activation and subsequent IL 2 production.
Phorbol esters inhibit the functional activation of cytotoxic precursors in mixed lymphocyte cultures.
Authors: Masucci M G , Torsteinsdottir S , Pear W , Carstensen A , Klein E
Published: December 2022

We have investigated the effect of phorbol esters on T cell activation and generation of suppressor and cytotoxic activity in mixed lymphocyte cultures (MLC). The presence of 30 nM P(Bu)2 during the sensitization phase inhibited the generation of allospecific cytotoxicity and also decreased the killing potential against NK-sensitive targets. The inhibition was not mediated by direct blocking of the lytic capacity nor by suppression of clonal expansion of cytotoxic cells through modulation of lymphokine production. The presence of P(Bu)2 enhanced cell proliferation, but inhibited the functional activation of lymphocytes and consequent generation of Dr antigen-positive T cells. Because the presence of the compound did not affect the MLC-induced generation of suppressor activity, it is likely that P(Bu)2 selectively blocks the maturation of cytotoxic precursors. Surface-marker analysis with OKT monoclonal antibodies revealed that the effects on lymphocyte activation were associated with a decrease in OKT3 and OKT4 reactivity and an increase in the percentage of OKT8-positive cells. The decrease in OKT4 reactivity was not due to selective loss of this lymphocyte subpopulation, because P(Bu)2 was equally mitogenic for the purified OKT4- and OKT8-positive subsets. The results suggest that the effect of P(Bu)2 on cell differentiation and its ability to modulate the expression of functional markers in lymphocyte subsets may interfere with T-T cell cooperation that controls the functional maturation of cytotoxic precursors.
Lymphocyte activation antigens. I. A monoclonal antibody, anti-Act I, defines a new late lymphocyte activation antigen.
Authors: Lazarovits A I , Moscicki R A , Kurnick J T , Camerini D , Bhan A K , Baird L G , Erikson M , Colvin R B
Published: December 2022

Lymphocyte activation entails a sequence of events identified by analyzing the time course of expression of various distinctive cell surface molecules on lymphocytes that appear early (before initiation of DNA synthesis), parallel with DNA synthesis and cellular proliferation, or late (after peak proliferation). In this study we present identification of a novel late lymphocyte activation antigen, Act I, utilizing a murine monoclonal antibody. Anti-Act I was identified in a fusion of NS1 with BALB/c spleen cells immunized with a human tetanus toxoid-reactive T lymphoblast line. Flow cytometry analysis shows that Act I antigen is present in markedly greater amounts on activated T and B lymphocytes than on resting, small peripheral blood lymphocytes. Act I expression by these lymphocytes is promoted by PHA, tetanus toxoid, or alloantigens and lags behind maximal thymidine incorporation by 1 to 2 days. Thymocytes can be triggered to express Act I antigen during maturation induced by PHA/T cell growth factor stimulation. In vitro, anti-Act I does not affect antigen- or lectin-stimulated T cell proliferation, T cell-mediated lymphocytotoxicity, or T cell growth factor-induced proliferation of T lymphoblasts. By immunoperoxidase analysis, Act I antigen is restricted to lymphoid tissue, staining many lymphocytes in the paracortex, germinal centers, and mantle zones of lymph nodes, tonsil, and spleen. By immunoprecipitation, the Act I antigen is a single band of 63,000 m.w. on reduced or nonreduced SDS gels. The distribution, size, time course, and functional correlates indicate that Act I is different from other known T cell activation markers detected with anti-Tac, OKT9, B3/25, OKT10, 4F2, CBL1, and anti-Ia-like antibodies. Although the function of Act I is still undetermined, it may serve as a useful marker of a late stage of activation in vitro and in vivo.
Human tonsil B lymphocyte function. II. Pokeweed mitogen-induced plasma cell differentiation of B cell subpopulations expressing multiple heavy chain isotypes on their surface.
Authors: Mudde G C , Verberne C J , de Gast G C
Published: December 2022

Human tonsil non-T cells were successfully separated into surface IgM+G-ve (sIgM+G-), sIgM+G+, sIgM-G-, and sIgM-G+ B cell fractions. The two-step separation technique used did not affect the pokeweed mitogen- (PWM) induced plasma cell differentiation of the B cells. The highest percentages of plasma cells after PWM stimulation were found in the sIgM- fractions, and the lowest percentage was in the sIgM+G- fraction (20.8 +/- 2.3%), the latter predominantly cytoplasmic mu-chain-positive (c mu +) (84.1 +/- 3.5%) plasma cells. In this fraction, almost no c gamma + plasma cells were found. The sIgM+G+ produced c mu + (47.5 +/- 7.5%), c gamma + (35.7 +/- 5.8%), and c alpha + (16.8 +/- 4.0%) plasma cells. All three isotypes were found on the surface of the B cells in this fraction before PWM stimulation. The sIgM-G- fraction contained about 10% plasma cells before stimulation, which were predominantly c gamma +. After PWM stimulation, primarily c alpha + (64.2 +/- 4.3%) plasma cells were found. The sIgM-G+ fraction produced both c gamma + (75.0 +/- 2.3%) and c alpha + (24.1 +/- 2.5) plasma cells. A mu to gamma class switch did not occur in vitro in the sIgM+G- fraction on PWM stimulation, and the sIgM+G+ fraction did not complete in vitro the mu to gamma switch it had started in vivo.
Biologic properties of interleukin 3. II. Serologic comparison of 20-alpha-SDH-inducing activity, colony-stimulating activity, and WEHI-3 growth factor activity by using an antiserum against IL 3.
Authors: Bowlin T L , Scott A N , Ihle J N
Published: December 2022

An antiserum was prepared against IL 3 and was characterized. Purified Ig from the serum precipitated iodinated IL 3. By using conditioned media from 35S-labeled WEHI-3 cells, a 28,000 dalton protein and a 14/16,000 dalton doublet were specifically immune-precipitated, indicating that the immune Ig reacted with a limited number of WEHI-3-derived proteins. The immune Ig comparably inhibited the ability of purified IL 3 to induce the expression of 20-alpha-SDH, to induce proliferation of the FDC-P1 factor-dependent cell line, or to induce colony formation by bone marrow cells in soft agar. These results support the concept that IL 3 mediates these diverse biologic activities. By using conditioned media from WEHI-3 cells or from an MLR, the immune Ig completely inhibited induction of 20-alpha-SDH or proliferation of FDC-P1 cells, demonstrating that all of the activity is associated with a factor serologically identical to IL 3 purified from WEHI-3-conditioned media. In contrast, the immune Ig did not inhibit bone marrow colony formation by partially purified CSF-2, demonstrating that serologically as well as biochemically, CSF-2 is distinguishable from IL 3. Similarly, the immune Ig did not inhibit IL 2-induced proliferation of a cloned cytotoxic T cell line.
Difference in requirement of macrophage products for concanavalin A-induced production of eosinophil chemotactic factor and macrophage chemotactic factor from guinea pig lymphocytes in vitro.
Authors: Hirashima M , Tashiro K , Sakata K , Yoshimura T , Hayashi H
Published: December 2022

Differences between the conditions for an eosinophil chemotactic factor (ECF) and macrophage chemotactic factor (MCF) production by lymphoid cells of mesenteric lymph nodes and spleen were studied in guinea pigs. If lymphoid cells were washed less than 4 hr after concanavalin A (Con A) stimulation and were cultured for an additional 24 hr, they failed to produce ECF, whereas Con A stimulation for 1 hr before washing was sufficient to stimulate them to produce MCF. Subsequently, it was shown that heat-labile soluble factors (termed ECF-PF) with potentiating activity for ECF production are produced from macrophages by 5 micrograms/ml Con A activation. When ECF-PF were added to the cell culture with 5 micrograms/ml Con A, the lymphoid cells could produce ECF even when they were washed 2 hr after Con A stimulation and were cultured for an additional 24 hr, suggesting that ECF-PF plays a critical role in the early stage of ECF production. The lymphoid cells were also able to produce ECF even when they were cultured with ECF-PF and a suboptimal dose of Con A (1 microgram/ml) for ECF production. Protein synthesis seemed to be essential for ECF-PF production. The ECF-PF activity was associated with two separated molecular fractions with m.w. of about 50,000 to 70,000 and of 10,000 to 20,000. It is thus suggested that ECF is produced from T cells by Con A stimulation under conditions which differ, at least, from those for MCF in the requirement of ECF-PF.
Reconstitution of an inactive antigen-specific T cell suppressor factor by incubation of the factor with prostaglandins.
Authors: Kato K , Askenase P W
Published: December 2022

Experiments were performed to test the hypothesis that prostaglandins are crucial to the ability of an antigen-specific T cell suppressor factor to deliver a suppressive signal. In the system employed, T suppressor cells release an antigen-specific factor (TsF) that suppresses the ability of effector cells to transfer contact sensitivity (CS) skin swelling responsiveness to adoptive recipients. Culture of TsF-producing cells in the presence of indomethacin caused production of an inactive TsF that could be reconstituted by incubation of this inactive factor with low concentrations of certain prostaglandins such as PGE2 or PGE1. Subsequently, nearly all the prostaglandins were removed by dialysis, and the reconstituted TsF then acted as an antigen-specific suppressor of CS effector cells. Neither the inactive factor nor prostaglandins were suppressive alone. Furthermore, the prostaglandins are crucial to the constitution of TNBSA-F, the non-antigen-binding subunit of the TsF that probably delivers the ultimate suppressive signal. These results provide a new type of antigen-specific role for prostaglandins in immunoregulation and indicate that simple, local, hormonal molecules in physiologic concentrations can have a crucial and long-lasting role in constituting the suppressive activity of antigen-specific regulatory macromolecules released by suppressor T cells.
Antigen recognition by H-2-restricted T cells. II. A tryptic ovalbumin peptide that substitutes for processed antigen.
Authors: Shimonkevitz R , Colon S , Kappler J W , Marrack P , Grey H M
Published: December 2022

A 17-amino acid tryptic peptide of chicken ovalbumin, designated P323-339, that substituted for processed antigen when presented by glutaraldehyde prefixed accessory cells to specific I-restricted T hybridomas was characterized. The peptide antigen could not be demonstrated to have any specific or stable interactions with accessory cell Ia antigens by either direct binding or functional assays for inhibition of specific T cell activation. In addition, the T cell receptor for I-restricted antigen had no affinity for free antigen alone. A rabbit antibody specific for the antigenic peptide inhibited presentation when introduced before but not after binding of the peptide to accessory cells. These results extend our earlier finding that accessory cell-mediated processing of chicken ovalbumin can be completely explained by the fragmentation of the native molecule into smaller m.w. peptides, and suggests that if an antigen/Ia complex is important in T cell activation, it forms significantly only in the presence of the T cell receptor for I-restricted antigen.
Idiotypic analysis of a monoclonal anti-Sm antibody. II. Strain distribution of a common idiotypic determinant and its relationship to anti-Sm expression.
Authors: Pisetsky D S , Semper K F , Eisenberg R A
Published: December 2022

The idiotypes borne by Y2, a monoclonal anti-Sm antibody of MRL-lpr/lpr mouse strain origin, were investigated to elucidate genetic mechanisms in this autoantibody response. An anti-Y2 anti-idiotypic antiserum was raised in a rabbit and was rendered specific for idiotype by extensive absorption with globulins of the B6 and BALB/c strains as well as the BALB/c myeloma UPC 10. By using a sensitive assay for idiotype by inhibition ELISA, the Y2 determinant was found to be commonly expressed in sera of MRL-lpr/lpr and MRL-+/+ mice. Moreover, sera of several normal strain mice also bore the idiotype and, in mice bearing the lpr gene, idiotype levels were increased 1.5 to fivefold, even in the absence of a serum anti-Sm response. The relationship of this idiotype to anti-Sm expression was further assessed by determining the idiotype content of affinity-purified anti-Sm antibodies from MRL-lpr/lpr mice. Anti-Sm from serum pools or individual animals showed no significant enrichment of the Y2 idiotype in comparison to unselected MRL-lpr/lpr IgG. These results suggest that the Y2 idiotype defines only a minor component of the anti-Sm autoantibody response, and that most antibodies with this determinant express other antigenic specificities.
The role of I-A/E molecules in B lymphocyte activation. I. Inhibition of lipopolysaccharide-induced responses by monoclonal antibodies.
Authors: Forsgren S , Pobor G , Coutinho A , Pierres M
Published: December 2022

A panel of 22 different monoclonal antibodies, including specificities against various antigenic clusters of I-A and I-E molecules, were probed over a wide range of concentrations for their ability to inhibit lipopolysaccharide-induced B lymphocyte proliferation and maturation to immunoglobulin-secreting plaque-forming cells (PFC). Most antibodies were competent to inhibit up to 80 to 100% of the response of appropriate target cells, although having little or no effect on irrelevant spleen cell cultures. Mixtures of either anti-I-A or anti-I-E specificities were more efficient inhibitors than individual antibodies, as shown by the average concentrations required for 50% inhibition (30 and 300 ng/ml, respectively). The selective role of I-A/E molecules in B cell activation was demonstrated by the failure of anti-K antibodies of the same isotype, bound in comparable amounts to target cells, to modulate B cell responses in parallel cultures. Fc receptor-mediated inhibitory effects were further excluded by equivalent inhibition obtained with anti-I-A antibodies of the IgM class. Anti-I-A/E antibodies appear to inhibit the inductive phase of B cell responses, as suggested by limiting dilution experiments performed in the presence of 50% inhibitory concentrations of antibodies: 50% of the control number of reactive clones were found to respond, but those that escaped inhibition developed to control sizes of progenies producing PFC.
IgG antibodies to secretory component in normal human serum.
Authors: Splawski J B , Woodard C S , Denney R M , Goldblum R M
Published: December 2022

While isolating free secretory component (FSC) by monoclonal antibody affinity chromatography, we demonstrated FSC-IgG complexes in human milk. We hypothesized that IgG antibody to secretory component (SC) might be transported into the milk from the serum. We therefore examined sera from 10 normal adults and 10 infants for IgG capable of binding to FSC in an enzyme-linked immunosorbent assay. Eight of 10 normal adult sera and nine of 10 infant sera demonstrated IgG binding to FSC with titers ranging from 1:54 to 1:4096. Quantitation of the IgG bound to FSC was hampered in adult sera by the binding of IgM and polymeric IgA to the FSC. Quantitation in five infant sera ranged from 0.5 to 6.4 micrograms/ml. A pepsin digest of an IgG fraction of serum demonstrated binding of the F(ab')2 fragments to the FSC. The specificity of the antibodies in human serum was evaluated by examining the binding to secretory IgA (sIgA) and FSC isolated from pooled human milk and polymeric IgA isolated from the ascitic fluid of a patient with an IgA myeloma. Eight of the 10 adults had antibody specific for FSC. Three of the eight, all female, also had antibody specific for sIgA. Two of the eight had antibody either to FSC and sIgA or to FSC plus an antibody that could bind to an epitope shared by sIgA and FSC. Competition experiments with monoclonal antibodies to human secretory component and sIgA were used to confirm and further define these specificities. The results of this study indicate that antibody to SC is common in normal adult and infant sera. The majority of antibodies seem to be directed against epitopes present on FSC but not on sIgA, which suggests sensitization to circulating or membrane-bound SC. The significance of these antibodies in normal human sera remains to be elucidated.
Enhanced release of oxygen metabolites by monocyte-derived macrophages exposed to proteolytic enzymes: activity of neutrophil elastase and cathepsin G.
Authors: Speer C P , Pabst M J , Hedegaard H B , Rest R F , Johnston R B
Published: December 2022

Macrophages at sites of inflammation are exposed to proteolytic enzymes derived from neutrophils, platelets, clotting factors, complement, and damaged tissues. To investigate the possible effect of proteases on the plasma membrane-mediated oxidative metabolic response of macrophages in inflammatory sites, cultured human monocyte-derived macrophages were treated in vitro with proteolytic enzymes and were then assayed for their ability to release superoxide anion (O2-) and hydrogen peroxide (H2O2) in response to stimuli. Macrophages pretreated for 1 to 20 min with trypsin, chymotrypsin, pronase, or papain, 0.1 to 200 micrograms/ml, released up to 3.5-times more O2- and H2O2 than did control (untreated) cells. This enhanced production of oxygen metabolites was observed by using either phorbol myristate acetate or opsonized zymosan as the stimulus. Macrophages were also "primed" for enhanced O2- release (2.3-fold) by pretreatment with a subfraction of granules extracted from human neutrophils. This subfraction contained primarily elastase and cathepsin G. Similar enhancement was observed with 60 ng/ml or purified human neutrophil cathepsin G (2.2-fold) and with 20 micrograms/ml of purified neutrophil elastase (3.3-fold). Priming by these neutrophil proteases could be blocked by specific inhibitors of their proteolytic activity. These results suggest that macrophages involved in an inflammatory response might be rapidly primed by proteases released from degranulating neutrophils. Primed macrophages could mount a more effective oxidative metabolic response to microorganisms or tumor cells, but might also cause greater tissue damage.
Kinetics of neutrophil accumulation in acute inflammatory lesions induced by chemotaxins and chemotaxinigens.
Authors: Colditz I G , Movat H Z
Published: December 2022

The influx of neutrophils into cutaneous lesions induced with the chemotaxins formylmethionyl-leucyl-phenylalanine (FMLP), platelet-activating factor (PAF), and alpha-casein, and the chemotaxinigens endotoxin and zymosan peaked at 2 to 4 hr and then rapidly declined. In contrast, concanavalin A (Con A) induced a biphasic influx of neutrophils with an initial peak at 2 hr and a subsequent, prolonged peak between 6 and 10 hr. When the kinetics of the neutrophil influx into lesions induced with FMLP at 10(-5) M, 10(-6.5) M and 10(-8) M were examined, it was found that a comparable proportion of the total cell influx entered lesions induced with each concentration of FMLP at each time point. This result indicates that the kinetics of the neutrophil influx into an inflammatory lesion is not dependent on the concentration of chemotaxin within the lesion. The inflammatory potency of FMLP, PAF, alpha-casein, Con A, and endotoxin were compared with leukotriene B4 (LTB4) and zymosan-activated plasma (ZAP) as a source of C5 fragments. Equipotent concentrations were 10(-4) M alpha-casein, 10(-5) M PAF, 10(-5.5) M LTB4 and Con A, 10(-6) M FMLP, 10(-7) M ZAP, and 10(-11) M endotoxin.
Monoclonal antibodies demonstrate multiple epitopes on the O antigens of Salmonella typhimurium LPS.
Authors: Elkins K , Metcalf E S
Published: December 2022

To investigate the complexity of the antigenic determinants presented on the surface of Salmonella typhimurium, a panel of murine monoclonal antibodies was generated and characterized. Hybridomas specific for S. typhimurium (strain TML, O antigens 1, 4, 12) were produced by immunization with acetone-killed and dried bacteria and standard fusion procedures. In this report, 15 such monoclonal antibodies, all of which bind lipopolysaccharide (LPS) extracted from S. typhimurium, are described. The fine specificity of these antibodies was assessed by examining the differential binding of each antibody to a panel of Salmonella strains, which selectively express different O antigenic determinants. This analysis defined several distinct categories of monoclonal antibodies of varying isotypes. Four anti-O:4-specific antibodies were identified. Two were specific for O:1. One antibody appears to react with the core polysaccharide of S. typhimurium LPS. Several of the monoclonal antibodies recognized LPS determinants that are presumably created by a combination of O antigens. For instance, one bound only to Salmonella strains that expressed both O:1 and O:12, whereas another bound only to those strains which expressed both O:4 and O:12. A group of three antibodies bound to any strain that simultaneously expressed O:1, O:4, and O:12. A distinct group of three monoclonal antibodies also bound strains that expressed O:1, O:4, and O:12, but only when the O:5 antigenic determinant was not present. The latter are, in that respect, S. typhimurium strain TML LPS-specific. The results of this analysis suggest that the epitopes of the S. typhimurium LPS molecule that are recognized by the host are considerably more complex than has been previously indicated by classical serology.
Rabbit class I MHC genes: cDNA clones define full-length transcripts of an expressed gene and a putative pseudogene.
Authors: Tykocinski M L , Marche P N , Max E E , Kindt T J
Published: December 2022

The rabbit cell line RL-5 was recently found to express only a single detectable major histocompatibility complex class I protein, in contrast to the multiple class I proteins expressed in cells of the mouse (K, D, and L) and human (A, B, and C). To clarify this difference in the rabbit major histocompatibility complex, we have begun an investigation of the class I genes expressed in the RL-5 cell line and here report the construction of 31 class I cDNA clones derived from RL-5 mRNA. Restriction endonuclease mapping has allowed classification of these clones into five groups, apparently representing five distinct class I mRNA transcripts. The sequence of a full-length cDNA from the predominant group (representing 26 of the 31 clones) reveals a typical class I structure, with an amino terminus that exactly matches the 36 amino terminal residues previously determined for the class I protein immunoprecipitated from RL-5. Complete sequence of a second distinct class I mRNA transcript was deduced from cDNA clones of the second largest group (representing two of the 31 clones). Although this transcript corresponds to a complete class I sequence, an anomaly in initiation sequence may preclude its translation in the proper reading frame. Comparison of the rabbit class I sequences to those of mouse and human revealed significantly higher homologies between the rabbit and the human than between mouse and rabbit or mouse and human sequences.