bluuebunny/crossref_metadata_2025 huggingface dataset:
Leukocyte Complement: Assembly of the Membrane Attack Complex of Complement by Human Peripheral Blood Leukocytes in the Presence and Absence of Serum
Authors: Sundsmo John S. , Curd John G. , Kolb William P. , Müller-Eberhard Hans J.
Published: December 2022

The specific neoantigenic determinants (neoAg) that are indicative of the assembled C5b-9 C complex are generated on the surface of peripheral blood leukocytes (PBL) during collection and processing of blood. Formation of neoAg on PBL could be prevented by collecting blood directly into 20 mM EDTA and, could be induced in vitro by adding autologous serum to isolated PBL that lacked neoAg. When neoAg was induced by the addition of serum containing 125I-labeled C8, the C8 was incorporated into a 23S complex which could be eluted from PBL.

A mechanism for neoAg formation on PBL independent of exogenous serum factors was detected when PBL were placed into culture in serum-free medium. Results with metabolic inhibitors and 14C-leucine suggest that PBL can synthesize C5 and assemble the C5b-9 complex. The possible relevance of these findings to the understanding of mechanisms of cell-mediated cytotoxicity is discussed.
Aging and the Immune Response
Authors: Gardner Ian D. , Remington Jack S.
Published: December 2022

In studies to determine the effect of aging on the cell-mediated immune response to Toxoplasma gondii, aged mice showed a delayed onset of macrophage activation during acute infection with T. gondii when compared with young mice of the same strain. Activation appeared to be biphasic, with a peak occurring during the acute infection, followed by a transient decline and then a return to the high levels which are characteristic of the chronic infection. Macrophage activation decreased after approximately 11 weeks of infection in young mice; the decrease was less with increasing age except in the very oldest mice which also exhibited a marked decrease in activation. Specific lymphocyte transformation to Toxoplasma antigen did not reveal any age-related decline during the acute infection. With increasing age during chronic infection, antigen-specific lymphocyte transformation was enhanced except in very old mice. These results suggest that the increased “antigenic load” in older mice (see accompanying paper) with the chronic infection may result in enhanced cell-mediated immunity, but that at the extreme of old age there is a major decline in the inductive mechanism which overrides this stimulation.
Generation of Low-Dose Paralysis in the Absence of the Ability to Secrete Antibody
Authors: Markham Richard B. , Stashak Philip W. , Prescott Benjamin , Amsbaugh Diana F. , Baker Phillip J.
Published: December 2022

(CBA/N ♀ × BALB/c ♂) F1 male mice carry an X-linked defect, originating from CBA/N mice, which renders them unable to generate an antibody response to SSS-III. Histocompatible (BALB/c ♀ × CBA/N ♂) reciprocal F1 male hybrids do not carry the X-linked defect and therefore generate a readily detectable PFC response to SSS-III, which can be adoptively transferred into nonresponding reciprocal F1 male mice. In the present work, we shown that this adoptive response could be inhibited in recipient (CBA/N ♀ × BALB/c ♂) F1 male nonresponding mice in which low dose paralysis had been induced. Evidence is presented which indicates that such suppression is of host rather than donor cell origin.

The capacity to develop low-dose paralysis, a phenomenon that is antigen specific and has been attributed to the action of suppressor T cells, indicates that nonresponding (CBA/N ♀ × BALB/c ♂) F1 males (and presumably the CBA/N progenitor strain) have the ability to recognize this antigen. Furthermore, since these animals fail to make a serum antibody response to SSS-III, the signal that activates suppressor T cells cannot be circulating antibody or antigen-antibody complexes. These findings are most consistent with the view that low-dose paralysis of the response to SSS-III is not dependent on antibody-mediated feedback inhibition; rather, it is an active process mediated by suppressor T cells.
B Lymphocyte Precursors
Authors: Fairchild Sally S. , Cohen J. John
Published: December 2022

After surface immunoglobulin-bearing (sIg+) cells are removed from mouse bone marrow on an anti-Ig immunoadsorbent column, precursors of bone marrow-derived (B) lymphocytes can be observed to differentiate in vitro. Expression of sIg occurs spontaneously on approximately 50% of the small lymphocytes during 3 days in culture. The rate of expression is accelerated by lipopolysaccharide (LPS), cyclic AMP, or the cyclic AMP phosphodiesterase inhibitor R020-1724; after 20 hr in culture approximately 35% of the small lymphocytes are sIg+ in induced cultures compared to 11% in controls. Acquisition of the ability to respond by proliferation to the mitogen LPS does not occur spontaneously in vitro but can be induced. Mitogen responsiveness in unfractionated bone marrow cells is increased by a 2-day preincubation with any of the inducing agents (cAMP, R020-1724, or LPS itself). However, anti-Ig column-passed marrow can be induced only with LPS or another mitogen, dextran sulfate, and this induction is prevented by BUdR and light. We propose that immature B cells express sIg, and then must undergo further differentiation, possibly linked to cell division, before becoming responsive to LPS. Agents that raise intracellular cAMP accelerate expression of sIg and mitogen responsiveness in two distinct cell populations, and may do so by accelerating new genetic programs after determination events.
Enhancement of Human Eosinophil Complement Receptors by Pharmacologic Mediators
Authors: Anwar A. R. E. , Kay A. B.
Published: December 2022

With the rosette technique, the ECF-A tetrapeptides (Val-Gly-Ser-Glu and Ala-Gly-Ser-Glu) and histamine, agents previously shown to be preferentially chemotactic for the eosinophil, markedly enhanced the expression of human eosinophil receptors for C3b. The enhancement was both dose- and time-dependent, and highly selective for the eosinophil since there was no evidence that C3b receptors on neutrophils or monocytes were altered by these pharmacologic agents even when varying concentrations of C3 were added to the indicator red cells. The agents similarly enhanced receptors for C4, but under the same conditions C3d and IgG (Fc) receptors were unaffected.

A number of other pharmacologic mediators including bradykinin and the prostaglandins PGE1, E2, and F2α had no apparent effect on eosinophil C3b receptors at the same molar concentrations (5 × 10-5 to 5 × 10-7 moles 1-1). However, a major histamine catabolite, imidazoleacetic acid, also recognized as an anaphylaxis-associated eosinophilotactic agent, enhanced eosinophil C3b receptors to a degree comparable to that of histamine. In contrast, l-histidine and the histamine catabolites, N-acetylhistamine, 1,4-methylhistamine, and 1-methyl-4-imidazoleacetic acid, had no eosinophil C3b receptor-enhancing effect. 5-hydroxytryptamine at the highest concentration tested (5 × 10-5 moles 1-1) gave enhancment of eosinophil C3b receptors which was approximately one-third of that achieved with the same concentration of the ECF-A peptides, histamine, or imidazoleacetic acid.

A human lung anaphylactic diffusate also enhanced eosinophil C3b receptors. Approximately 10 times more synthetic histamine than that contained in the lung-derived material was required for comparable enhancement, indicating that the histamine and ECF-A peptides present in the diffusate may have combined to give optimal enhancing effect. However, when synthetic histamine and the valyl- or alanyl-peptide, were mixed in various proportions, the enhancement was no greater than that achieved when each agent was tested alone.

These results suggest that pharmacologic mediators of hypersensitivity may regulate certain eosinophil-dependent biologic reactions and that there may be a direct relationship between the cell surface “recognition unit” for eosinophil locomotion and some of the membrane receptors that promote the adhesion of eosinophils to opsonized particles.
Regulation of Human Lymphocyte Function by a Soluble Extract from Normal Human Liver
Authors: Chisari Francis V.
Published: December 2022

The blastogenic and DNA synthetic response of human peripheral blood lymphocytes (PBL) to phytohemagglutinin (PHA) and allogeneic cells can be inhibited by a nontoxic aqueous extract (LEx) of normal human liver. LEx reversibly inhibits the activation of PBL by PHA, arrests ongoing DNA synthesis, and limits the duration of the DNA synthetic response to PHA at concentrations as low as 0.7 to 1.5 µg LEx protein/culture. In contrast, human T lymphocyte E rosette formation is unaffected by LEx concentrations in excess of 900 µg/culture. LEx has been partially purified by ultracentrifugation, ammonium sulfate precipitation, and molecular exclusion chromatography and appears to be a heat labile protein with a m.w. of approximately 65,000 and an isoelectric point of approximately 4.08. LEx is distinct from other previously described human immunoregulatory molecules and is potentially releasable in vivo from injured or necrotic liver cells. Because of its potency and anatomic distribution LEx may potentially modulate immunopathogenetic events responsible for assorted inflammatory and neoplastic liver diseases.
Estimates of the Precursor Frequency of Cytotoxic T Lymphocytes against Antigens Controlled by Defined Regions of the H-2 Gene Complex: Comparison of the Effect of H-2 Differences Due to Intra-H-2 Recombination VS Mutation
Authors: Pimsler Meade , Forman James
Published: December 2022

Lymph node cells were sensitized in a limiting dilution assay against B10.D2 (H-2d) and the frequency of cytotoxic T lymphocyte (CTL.P) precursors was determined. A mean CTL.P frequency of 0.047% was observed when responding strains differed from the stimulators at the entire H-2 gene complex. When intra-H-2 recombinant strains were sensitized against B10.D2, lower frequencies of CTL.P were observed. Responding strains that differed from the stimulators at the H-2K-end only had 2- to 6-fold more CTL.P compared to strains sensitized against the D-end only.

In order to study the CTL.P frequency against minor antigenic differences, the B10.D2 (M504-H-2da) mutant strain, which carries a mutation with an antigenic gainloss in the D-region of H-2d, was examined. This mutant showed an identical CTL.P frequency against H-2d as H-2D-end recombinant strains. Therefore, this H-2 mutant (M504) has either undergone extensive mutation or the qualitative nature of the antigenic loss in this strain results in a high CTL.P frequency against the strain of origin.
IgG Antibodies Produced by Heterozygous a1a3 Rabbits Responding to Acidic Azohaptens Are Predominantly of Allotype a1
Authors: Chien Chau-Chun , Ingraham Joseph S.
Published: December 2022

Rabbits of allotype a1a3 were immunized with one of three acidic hapten-bovine serum albumin (BSA) conjugates: p-azophenyl arsonate (AA)-, p-azophenyl sulfonate (SA)-, or p-azobenzoate (CA)-BSA; all animals also received the basic conjugate, p-azophenyl-N-trimethyl-ammonium (TMA)-BSA. After 6 to 12 months, each animal was challenged with the same combination of BSA conjugates as given originally. The allotype of the plaque-forming cells (PFC) from lymph nodes and spleen was determined by enhancement with anti-allotype antisera. PFC detected upon addition of anti-a1 were designated a1-PFC and those detected with anti-a3 were designated a3-PFC. Results were expressed as the ratio of a1-PFC to a3-PFC. For the basic hapten, TMA, this ratio was 0.2 to 1.0 for nine lymph nodes and 0.3 to 1.6 for seven spleens. In contrast, the ratio for the acidic haptens was much higher: for AA, from 4 to 16 in three lymph nodes and 24 to 87 in two spleens; for SA, from 4 to 114 in three nodes and 38 to 59 in two spleens; for CA from 13 to 130 in two nodes and 4 to 33 in three spleens. Analogous use of anti-allotype sera for enhancement of anti-acidic hapten hemolytic serum titers showed that anti-a1 gave 8 to 16 times the enhancement given with anti-a3. Thus, the results indicate that the a1a3 rabbits made little or no antibody of allotype a3 during the secondary response to these acid haptens.
Kinetic Analysis of Antibody-Dependent Cellular Cytotoxicity: Evidence for Noncompetitive Inhibition by Autologous Lymphoid Cells
Authors: Herrick Michael V. , Pollack Sylvia B.
Published: December 2022

Inhibition of antibody-dependent cellular cytotoxicity (ADCC) by autologous lymphocytes was analyzed by using classical techniques for enzyme-substrate interactions. We determined empirically that the interaction of murine spleen cells with antibody-coated targets to produce lysis was analogous to the interactions that have been described for an enzyme with its substrate. Varying numbers of antibody-coated target cells (“substrate”) were mixed with a constant number of spleen cells (“enzyme”) and the number of target cells killed (“product”) was measured as a function of time. By analogy with Michaelis-Menten enzyme kinetics, two parameters of the reaction were determined: Vmax, the maximum velocity of lysis that is proportional to the number of killer cells present, and K½, an intrinsic property of the killer cells. These parameters were found to be independent variables. Addition of autologous lymph node cells produced a dose-dependent decrease in Vmax whereas K½ was not significantly changed. By analogy with enzyme kinetics, this inhibition is noncompetitive, suggesting that the autologous lymphocytes inactivate the killer cells rather than competing for the cell-cell binding sites.
Liposomes As Model Membrane Systems for Immune Attack
Authors: Ozato Keiko , Ziegler H. Kirk , Henney Christopher S.
Published: December 2022

The interaction of human peripheral blood lymphocytes with liposomes containing DNP-aminocaproylphosphatidylethanolamine together with either egg yolk or dipalmitoylphosphatidylcholine has been investigated. When lymphocytes were incubated with liposomes at 37°C, the aqueous compartment (86Rb+) and the lipid portion (3H-lipid) of the liposomes became cell associated to an equivalent extent. At 0°C, however, the incorporation of 3H-lipid exceeded that of 86Rb+. Lymphocyte-liposome interactions were accompanied by the transfer of DNP to the surface of the lymphoid cell as measured by susceptibility to complement in the presence of anti-DNP antibody. Hapten transfer was not limited to liposome interactions with lymphocytes, but occurred also with other cells (e.g., Chang cells). Hapten transfer could also be demonstrated by susceptiblity to K cell-mediated lysis. These findings suggest that liposomes may prove to be a useful vehicle for the transfer of new antigenic determinants onto cell surfaces. The implications of these findings are discussed in the context of using liposomes as targets for cell-mediated cytotoxic attack.
The Importance of an Intact Complement Pathway in Recovery from a Primary Viral Infection: Influenza in Decomplemented and in C5-Deficient Mice
Authors: Hicks John T. , Ennis Francis A. , Kim Elizabeth , Verbonitz Martha
Published: December 2022

To investigate the role of complement (C) in the recovery from a primary viral infection in vivo, the course of influenza infection in decomplemented BALB/c mice and in C5-deficient B10.D2/OSN mice was examined. BALB/c male mice decomplemented with cobra venom factor demonstrated a prolonged viral infection, an increased degree of pulmonary consolidation, and a higher rate of morbidity and mortality than did nondecomplemented mice for each dose of virus administered. This deleterious effect occurred in mice decomplemented before infection and immunologic induction, as well as in mice decomplemented after infection and immunologic induction, provided the C3 levels remained depressed at the time of viral clearance (days 7 to 9). The time of appearance and the levels of serum neutralizing antibodies and viral-specific cytotoxic T cells were equivalent in decomplemented and nondecomplemented BALB/c mice infected with influenza. Similarly, C5-deficient B10.D2/OSN male mice, infected with influenza, demonstrated a prolonged viral infection, an increased degree of pulmonary consolidation and a higher rate of mortality than did C5-sufficient B10.D2/NSN agematched mice for each dose of virus administered. These results suggest than an intact complement pathway plays an adjunctive role in host recovery from primary influenza infection.
Mechanisms of Regulation of Cell-Mediated Immunity
Authors: Bach Bruce Allen , Sherman Linda , Benacerraf Baruj , Greene Mark Irwin
Published: December 2022

We have investigated the induction, transfer, and suppression of delayed-type hypersensitivity (DTH) to the hapten azobenzenearsonate (ABA), using ABA-derivatized spleen cells in mice. It was found that ABA-derivatized syngeneic cells administered subcutaneously induced hapten-specific DTH responses detected by footpad swelling upon challenge with similarly ABA-modified syngeneic cells, but not with syngeneic cells modified with an irrelevant hapten. The footpad response was determined to be a manifestation of cell-mediated immunity (CMI) from the time course of the reactivity, the characteristic histology, and the results of adoptive transfer experiments. Negative selection experiments with anti-Thy 1.2 antiserum and complement demonstrated that the response was thymic dependent (T) and was transferable to naive recipients by immune T cells but not by immune sera. The induction and elicitation of the response required, minimally, identity at the I-A region of the H-2 major histocompatibility complex (MHC) between the immunizing hapten-modified cell and the recipient. Further studies revealed that syngeneic ABA-modified adherent cells were more capable of inducing ABA-specific DTH responses than similarly derivatized nonadherent cells. Studies dealing with the presentation of hapten with (BALB/c × A/J)F1 derivatized cells as immunogens indicated that F1 immune mice appeared to respond preferentially to BALB/c hapten cell surface conjugates rather than A/J cell surface as assessed by challenge of F1 immune mice with modified parental cells of either type.

In adoptive transfer experiments it was found that immune T cells could transfer reactivity if, and only if, the immune T cells, the recipient, and the challenging modified cell were syngeneic or semisyngeneic. Allogeneic transfers were unsuccessful, even when the priming cells, the immune T cells, and challenge were syngeneic, but the recipient was not. The apparent failure of allogeneic transfer was not due to the presence of suppressor cells.

Finally, we were able to elicit suppressor T cells by the i.v. administration of ABA-modified syngeneic cells. ABA-specific suppressor T cells limit the generation of DTH to ABA-modified cells, but do not decrease DTH to cells modified with an irrelevant hapten.
Cellular and Genetic Control of Antibody Responses in Vitro
Authors: Hodes Richard J. , Ahmann Gerald B. , Hathcock Karen S. , Dickler Howard B. , Singer Alfred
Published: December 2022

The expression of Ia antigens by accessory cells participating in in vitro primary antibody responses, including responses under Ir gene control, has been investigated. The ability of radiationresistant, non-T, non-B, spleen-adherent cells to function as accessory cells has been demonstrated both for the Ir gene-controlled response to TNP-(T,G)-A--L and for the response to TNP-KLH, for which no Ir gene control has been demonstrated. Pretreatment of these adherent accessory cells with anti-Ia reagents and complement totally abrogated the accessory function of this population for responses to both antigens. This abrogation of accessory function resulted from the elimination of accessory cells, rather than from any active suppression of responsiveness, either by carry-over of anti-Ia antibody or antigen-antibody complexes. By using appropriate recombinant strains and specific anti-Ia reagents, it has further been demonstrated that Ia determinants encoded in at least two I subregions, I-A and I-E/C, are expressed on accessory cells for responses to TNP-KLH and TNP-('T,G)-A--L; and that determinants encoded in at least two I subregions are expressed simultaneously on the same cells. The data presented also suggest that the functionally active Ia-positive accessory cell is itself either nonphagocytic or constitutes a subpopulation of phagocytes expressing Ia antigens encoded in at least two I subregions.
In Vitro Studies of the Rabbit Immune System
Authors: Redelman Doug , Trefts Park E.
Published: December 2022

Xenogeneic rabbit anti-mouse cell-mediated cytotoxic activity could be generated by culturing lymphoid cells from mesenteric lymph nodes (MLN), spleen, or peripheral blood of rabbits primed 2 to 8 weeks earlier with mouse tumor or spleen cells. MLN cells, which provided the best source of activity after being cultured with 5 to 10 × 106 mitomycin C-treated mouse spleen cells for 4 to 6 days, produced 30 to 90% specific isotope release after 4 to 7 hr incubation with 15Cr-labeled tumor target cells. Xenogeneic cytotoxic activity was primarily H-2 specific and could not be blocked by immune complexes but was abrogated by treatment with goat anti-rabbit thymocyte serum plus complement (ATS + C) before or after culture. Therefore, the activity appeared to be mediated by cytotoxic T lymphocytes (CTL). Furthermore, ATS without C abrogated cytotoxic activity when included in the CTL assay at concentrations of 5 to 15 µl/107 effector cells. The inhibitory activity of ATS was directed to the rabbit effector population and could be adsorbed completely by rabbit thymocytes. Antisera to mouse T cells with comparable cytolytic activity in the presence of C did not inhibit murine allogeneic CTL.
Studies on the Mechanism of Lymphocyte-Mediated Cytolysis
Authors: Green William R. , Ballas Zuhair K. , Henney Christopher S.
Published: December 2022

The role of lectin in lectin-dependent cell-mediated cytolysis has been pursued by using alloimmune C57BL/6 spleen cells as a source of effector cells and EL4 lymphoma cells, syngeneic to the effector, as targets. Of a variety of lectins studied, in this system, only the T cell mitogens concanavalin A (Con A), Lens culinaris hemagglutinin A, and leucoagglutinin derived from phytohemagglutinin were able to support cytolysis. Agglutinating agents that were not mitogenic, such as wheat germ agglutinin or antisera against the interacting cells, did not promote cytolysis. B cell mitogens were similarly unable to support lysis even when co-incubated with agglutinating agents.

The role of the T cell mitogens in lectin-dependent cytolysis appeared to be 2-fold: “activation” of the effector cell to express its cytotoxic potential and “bridging” of the effector cell to its target. These conclusions were based on the findings that: a) agglutination of target cells to T effector cells, although necessary to elicit cytolysis, was in itself insufficient, and b) T cells “activated” by mitogen under conditions which precluded cell-cell bridging did not lead to lysis.

Furthermore, we could find no evidence that the bridging function of the lectin during cytolysis could be served by agents other than T cell mitogens. This might explain our finding that the Ca++ ionophore A23187, which others have shown to substitute for Con A in the early stages of a mitogenic response, but which does not cause cell agglutination, did not mediate cytolysis, even in the presence of nonmitogenic agglutinins.

These findings of stringent requirements for both the “activating” and “bridging” roles of lectin during cytolysis necessitate radical revision of previous notions that the lectins serve merely as a “glue.”
Biosynthesis of the First Component of Complement by Human and Guinea Pig Peritoneal Macrophages: Evidence for an Independent Production of the C1 Subunits
Authors: Müller Wolfgang , Hanauske-Abel Hartmut , Loos Michael
Published: December 2022

The first component of complement, C1, was produced by human as well as guinea pig macrophages. Supernatants from serum-free cultured macrophage monolayers, tested separately for C1q and C1 activity, showed a ratio of 15:1, respectively, and a different time course of C1q and C1 production, indicating that the subcomponents of C1 are synthesized independently. Heat-inactivated fetal calf or guinea pig serum (2 hr, 56°C), added to the culture medium, were found to be inhibitory for C1 but not for C1q activity, obviously due to still active C1 inhibitor in these sera. De novo synthesis was confirmed by reversible inhibition of C1 and C1q production by cycloheximide (0.5 µg/ml) and puromycin (1 µg/ml), by incorporation of radiolabeled amino acids into the C1s subcomponent, and by uptake of incorporated radioactivity by EA, which was sensitive to EDTA. In additional experiments, 2,2′-dipyridyl markedly reduced C1q and also C1 secretion in the supernatants. Inhibition of the prolyl and lysyl hydroxylation and, as a consequence, structural instability of the collagenous region in the C1q molecule, is discussed as the cause of this effect which is analogous to collagen biosynthesis.
Immunologic Characterization of Tumor-Associated Transplantation Antigens on MM102 Mammary Tumor Eliciting Preferentially Helper T Cell Activity
Authors: Fujiwara Hiromi , Aoki Hisakazu , Tsuchida Tetsuo , Hamaoka Toshiyuki
Published: December 2022

The immunologic nature of tumor-associated transplantation antigens (TATA) of MM102 mammary tumor that originated spontaneously in C3H/He (H-2k) mice was analyzed. The TATA of MM102 tumor have been demonstrated in our laboratory to induce preferential generation of helper T cell activity without any significant killer T cell generation. The helper T cells that were generated by the immunization of syngeneic C3H/He mice with MM102 tumor and specifically reactive to the TATA of MM102 tumor were also reactive with the cellsurface antigens present on the normal or malignant lymphoid cells of allogeneic C57BL/6 (B6) and C57BL/10 (B10) mice. The reactivities of such TATA-reactive helper T cells were eventually the same irrespective of whether those lymphoid cells are derived from B10 (H-2b) mice or B10.BR (H-2k), the congenic strain of the same B10 background. Furthermore, in addition to the fact that the immunization of C3H/He mice with those lymphoid cells could induce the resistance against the challenge with viable MM102 cells, C3H/He mice that had been neonatally rendered tolerant to B10.BR could not develop the immune resistance against MM102 tumor.

These results clearly indicate that TATA of MM102 tumor are closely similar or identical to the non-H-2 antigens of allogeneic B10 mice on the level of helper T cell recognition, and that those non-H-2 alloantigens are capable of acting as the adequate transplantation antigens required for the effective induction of immune resistance against MM102 tumor.
Heterogeneity of I-J Subregion Gene Products: Their Expression on Functionally Different Subsets of T Cells
Authors: Tada Tomio , Okumura Ko , Tokuhisa Takeshi , Nonaka Makoto , Taniguchi Masaru
Published: December 2022

I-J subregion was originally identified by a locus, Ia-4, which controls a cell surface molecule on suppressor T cells (Ts). By the occurrence of two pairs of recombinants, B10.A(3R) and B10.A(5R), and B10.S(9R) and B10.HTT, which differ in the haplotype origin of Ia-4, I-J subregion was defined as a segment intercalated between I-B and I-E subregions. It has been shown that the suppressive T cell factor (TsF) is derived from Lyt-2+, 3+ T cells and can be absorbed by anti-I-J antisera. The acceptor site for the TsF on Lyt-1+, 2+, 3+ cells is also blocked by anti-I-J. A question remains to be solved as to whether or not the TsF and acceptor are coded for by the same locus. Moreover, we have recently shown that some but not all helper T cells carry determinants coded for by genes in I-J subregion.
Chemical Characterization of Rat Ia Antigens
Authors: Blankenhorn Elizabeth P. , Cecka Michael , Götze Dietrich , Hood Lee
Published: December 2022

Ia antigens from two inbred strains of rats have been characterized by two-dimensional gel (IEF/SDS PAGE) and microsequence analysis. Rat Ia antigens are isolated from biosynthetically radiolabeled spleen cells using semicongenic alloantisera. Rat Ia antigens are composed of two components on SDS-PAGE as are their mouse, human, and guinea pig counterparts. The larger polypeptide (α) has an apparent molecular weight of 33,000. The α polypeptides of AgB3 and AgB4 haplotypes show striking homology in their partial N-terminal amino acid sequences to the mouse ECαk and ECαd polypeptides and to human P34. The rat B3 and B4 α polypeptides are identical at six of eight positions which can be compared. The smaller polypeptide (β) has an apparent molecular weight of 28,000. Preliminary data on the β polypeptides suggest the existence of multiple molecular species for each haplotype. Sequences resembling mouse IA-β and I-EC-β polypeptides may be present.
Structural Differences Between the Ia Antigens Determined by the I-A and I-C Subregions
Authors: Cullen Susan E. , Littman Dan R. , Schwartz Benjamin D.
Published: December 2022

Ia antigens isolated from radiolabeled spleen cells by immune precipitation from detergent extracts using subregion specific anti-Ia sera showed superficial structural similarity. Under nonreducing conditions, subregion-specific differences were found. The α(∼35,000 dalton) and β(∼25,000 dalton) chains of Ia molecules determined by the I-A subregion of haplotypes b, d, f, k, g, r and s were found partly in a disulfide linked form (∼58,000 daltons, “58K”) but those determined by the I-C subregion of haplotypes d, k, p and r were not linked. Reduction of isolated 58K material produced electrophoretic peaks equivalent to α and β.

The I-A determined molecules were distributed between 58K and α + β forms, and the ratio of 58K to α + β could be reduced by alkylating before detergent solubilization. It is not yet clear whether the I-A determined molecules which assume the 58K form are different from those which remain in the α + β forms.
Analysis of the Role of Phagocytic Cells in the Generation of H-2-Restricted T-Cytotoxic Effectors to Trinitrophenyl-Conjugated Proteins and Trinitrophenyl-Modified Cells
Authors: Pettinelli C. B. , Schmitt-Verhulst A.-M.
Published: December 2022

Mouse spleen cells cultured in the presence of trinitrophenyl-(TNP)-conjugated proteins such as bovine serum albumin (TNP25–40-BSA) generate T-cytotoxic effector cells which exhibit similar properties to those obtained by sensitization with trinitrobenzene sulfonate-(TNBS)-modified syngeneic cells. Both types of cytotoxic effectors are TNP specific and exhibit H-2K- and/or D-associated recognition.

Studies analyzing the cellular presentation of TNP-BSA indicated that TNP-BSA could be detected on the surface of TNP-BSA-preincubated spleen cells and that such cells could serve as stimulators for the generation of H-2 restricted syngeneic cytotoxic effectors. Depletion of phagocytic cells from spleen cells prior to their incubation with TNP-BSA did not affect their stimulating capacity, indicating that the interaction of the TNP-protein with the cell surface was not mediated by a phagocytic mechanism. However, when both responding and stimulating cell populations were depleted of phagocytic cells, no cytotoxic effector cells were generated either to TNP-BSA or to TNBS-syngeneic cells.
Ir Gene Control of Cytolytic T Lymphocytes Induced by TNP Modified Syngeneic Cells in Normal and Chimeric Mice
Authors: Burakoff Steven , Billings Paul , Dorf Martin , Benacerraf Baruj
Published: December 2022

Cytolytic T lymphocytes (CTL) generated to trinitrophenyl (TNP) modified syngeneic cells from mice bearing the H-2b,d,r,s haplotypes exhibit cytolytic activity toward TNP modified syngeneic target cells, however they also demonstrate significant levels of cross reactive lysis of TNP modified allogeneic targets. In contrast, CTL from strains bearing the H-2k haplotype are H-2 restricted, only lysing TNP modified syngeneic targets. This inability to cross-reactively lyse TNP modified allogeneic targets is a defect of the responder cell and not the stimulator. Specifically, (B6 × C3H)F1 spleen cells demonstrate cross-reactive lysis when stimulated by either TNP modified C57BL/6 or TNP modified C3H stimulator cells. Utilizing H-2 recombinant strains we have mapped the genes controlling this H-2 retriction to the K and/or IA loci. Thus, this appears to be an Ir gene-like phenomenon.

Bone marrow cells from C3H mice were allowed to mature in a lethally irradiated (B6 × C3H)F1 host to determine whether the host environment influenced CTL specificity.
Regulation of Suppressor T Cell Function Specific for Ir Controlled Antigens
Authors: Germain Ronald N. , Pierres Michel , Waltenbaugh Carl , Benacerraf Baruj
Published: December 2022

I-region-coded nonresponder T cell-derived suppressor extracts (TsF) specific for l-glutamic acid60-l-alanine30-l-tyrosine10 (GAT) or l-glutamic acid50-l-tyrosine50 (GT) induce T suppressor cells (Ts2) in vivo and in vitro in nonresponder spleen cells. This induction requires both an I-J subregion coded TsF and also specific antigen. The Ts2 cells are I-J+ and do not acquire these I-J determinants from passively adsorbed TsF. Further, Ts2 are highly antigen specific, being able to selectively suppress GAT vs GT-MBSA responses in the same strain. In the GT model, H-2a mice fail to produce GT-TsF, while H-2b mice cannot yield active Ts2 when exposed to GT-TsF. (B6A)F1 mice complement for GT suppression by reciprocal parental contribution of the missing suppressor components. No H-2 identity requirements for Ts2 generation by TsF have been noted in nonresponders, and Ts2 induction by nonresponder TsF can also occur in responder spleen cells, indicating lack of requirement for Ir matching between TsF donor and recipient.
Report of Ia Nomenclature Workshop Session
Authors: Sachs David H.
Published: December 2022

There have been three previous workshop sessions on the nomenclature of Ia antigens, each held as a special session of a larger workshop or meeting, and reports from each of these nomenclature sessions have been published (1–3). The reader is referred to these references for a detailed listing of the agreements and recommendations for Ia nomanclature reached at each of these previous sessions. The present session was held in order to review the status of Ia nomenclature, to discuss nomenclature problems that have arisen since the last such session, and to discuss the need for any possible changes in nomenclature to accommodate the rapid expansion that is still occurring in the field of Ia antigens. This report is a summary of the topics discussed.
Two Subgroups of T Helper Cells in F1 Hybrid Mice Revealed by Negative Selection to Heterologous Erythrocytes in Vivo
Authors: Sprent Jonathan
Published: December 2022

The specificity of heterozygous T cells for H-2-associated antigen in vivo was studied by inducing negative selection to sheep erythrocytes (SRC) in irradiated mice. Purified (CBA × C57BL/6)F1 T cells plus SRC were transferred to irradiated F1 or parental strain mice and then recovered from thoracic duct lymph 1 to 2 days later to measure T helper function. When F1 T cells were filtered with SRC through irradiated F1 mice the cells lost the capacity to stimulate anti-SRC responses by CBA, C57BL/6 or F1 B cells. The unresponsiveness was specific (normal responses were found against horse erythrocytes) and there was no evidence that suppression was involved. By contrast, F1 T cells filtered with SRC through irradiated mice of one parental strain failed to stimulate anti-SRC responses by B cells of this strain but retained the capacity to stimulate B cells of the opposite parental strain and F1 B cells. Both primed and unprimed T cells gave similar results and subsequent positive selection of the T cells to SRC in irradiated F1 mice for 5 days did not abrogate the restriction. The phenomenon was shown to be linked to the H-2 complex but not to Ig allotype.

The data provide further support for the view that F1 T cells comprise two subgroups of cells and imply that only one subgroup undergoes negative selection (is transiently withdrawn from the circulation) when exposed to antigen in irradiated mice of one parental strain. Both T cell subgroups undergo selection in irradiated F1 mice.
Quantitative Studies on the Precursors of Cytotoxic Lymphocytes
Authors: Teh H.-S. , Phillips R. A. , Miller R. G.
Published: December 2022

The cytotoxic response to TNP-modified syngeneic cells is small compared to the cytotoxic response to alloantigens. Limiting dilution analyses indicate that the number of lymphocytes in C57BL/6J(B6) lymph nodes responding to DBA/2J(D2) and B6-TNP are 1199 and 40 per 106 cells, respectively. These cytotoxic T lymphocytes (CL) produced as a result of stimulation of B6 lymphocytes with B6-TNP also lyse D2-TNP targets. Clonal analyses show that this cross-reactivity is a result of strong recognition of D2-TNP targets by 40% of B6-TNP specific CL and not relatively weak recognition of D2-TNP by all B6-TNP specific CL. When (C57BL/6J × DBA/2J)F1 mice (BDF1) were stimulated with BDF1-TNP, about 67% of the cytotoxic clones that lysed B6-TNP also lysed D2-TNP target cells; clones specific for either B6-TNP or D2-TNP were also produced. Cold target competition studies suggest that the higher degree of cross-reactivity in the latter case cannot be explained on the basis of the existence of antigenic specificities unique only to the F1 hybrid cells. Nor is the anomalously high F1 cross-reactivity due to the absence of parental antigenic specificities on the F1 cells. One possible explanation for these data is that the repertoire of cytotoxic precursors of the F1 hybrid for TNP-modified self antigens may be different from the sum of the repertoires for the parents.
Purification and Characterization of Mouse Brain Thy-1 Glycoprotein Antigens
Authors: Letarte Michelle , Meghji Gulzar
Published: December 2022

Thy-1 antigens have been isolated from C57BL/10 mouse brain. Thy-1 antigenic activity was followed during purification by measuring the rat-mouse cross-reacting determinants of the Thy-1 molecule that were recognized by a rabbit antiserum prepared against Thy-1 glycoprotein isolated from rat brain. After solubilization with deoxycholate, mouse brain Thy-1 antigens were purified by affinity chromatography to Lens culinaris lectin and by gel filtration. A 923-fold enrichment in Thy-1 activity and a 26% yield were obtained; the antigenic activity was associated with a glycoprotein of m.w. 25,000 estimated by SDS gel electrophoresis on 10% acrylamide gels.

The serologic and biochemical properties of Thy-1 molecules purified from mouse (Thy-1.2) brain were very similar to those of Thy-1 molecules purified from rat (Thy-1.1) brain and thymus. Heteroantisera produced against mouse brain Thy-1 glycoprotein detected mouse-specific as well as rat-mouse cross-reacting determinants of the Thy-1 molecule but did not discriminate between Thy-1.1 or Thy-1.2 alloantigens.

The presence of Thy-1.2 determinants on purified Thy-1 glycoprotein could be demonstrated only in the absence of detergent. In deoxycholate, monomeric Thy-1 molecules were unable to block either binding or cytoxic activity of anti-Thy-1.2 sera; after removal of deoxycholate, aggregated Thy-1 molecules could partially block the binding or the cytotoxic activity of anti-Thy-1.2 sera. Other antigenic determinants of the molecule were not affected by detergent.
Regulation of Alloantigen-Induced Cytotoxic Responses by Concanavalin A-Activated Lymphoid Cells: Suppression by Antigen Elimination
Authors: Kastner Daniel L. , Rich Robert R.
Published: December 2022

Spleen cells activated by concanavalin A (Con A) and subsequently irradiated with 1500 R were able to suppress the primary in vitro cytotoxic lymphocyte (CL) response of syngeneic splenocytes to H-2 disparate targets. Similarly activated and irradiated BALB/c (H-2d) splenocytes which were cultured with C57BL/6 (H-2b) stimulators for 24 hr developed cytotoxicity for H-2b, but not H-2d, tumor cell targets. This suggested that Con A-activated cells allogeneic to the stimulator might suppress the development of cytotoxic lymphocytes by eliminating antigen early in mixed leukocyte culture. This hypothesis was supported by the observation that suppression of primary cytotoxic responses was overridden by the use of greater numbers of stimulator cells. Moreover, Con A-activated (A × B)F1 lymphocytes suppressed the response of parent A to the H-2 disparate strain C to a much greater extent than they suppressed A-anti-B responses generated in such cultures. Addition of greater numbers of F1 suppressor cells did reveal a suppressive effect not readily explicable on a cytotoxic mechanism, in that modest but significant suppression of the A-anti-B response was observed. Thus, antigen elimination is a major, but not exclusive, mechanism in the suppression of CL responses by Con A-activated cells.
The Effects of Passive Immunization with Tumor-Specific Antiserum on the Active Immune Response of Mice to Sublines of Leukemia L1210
Authors: Carlson George A. , Terres Geronimo
Published: December 2022

In vivo, tumor cell killing was monitored with 131I-IUdR-labeled tumor cells and whole-body measurement of retained radioactivity. Treatment with antiserum in quantities that were not sufficient to kill the total leukemia cell inoculum (i.e., antigen excess) caused an immunopotentiation of the active immune response; this was manifested by an accelerated rate of tumor cell killing beginning between days 10 and 11. The results obtained in vivo were confirmed by in vitro quantitation; both the cytotoxic antibody and cell-mediated immune responses were potentiated by the injection of antiserum. Immunosuppression was also observed in passively immunized mice. Whether potentiation or suppression occurred was dependent on the relative amounts of antiserum and leukemic cells injected and the innate immunogenicity (and/or antigenicity) of the leukemic cells; antibody excess and high immunogenicity favored suppression.
Mechanism of Macrophage-Mediated Tumor Cell Cytotoxicity
Authors: Kaplan Alan M. , Brown Judith , Collins James M. , Morahan Page S. , Snodgrass Michael J.
Published: December 2022

Activated macrophages inhibit the incorporation of 125IUDR into the DNA of Lewis lung cells and lead to the cytotoxicity of these target tumor cells. Despite this apparent inhibition of DNA synthesis, an early increase in the number of Lewis lung (LL) cells occurs when LL is cultured with activated macrophages. This increase in the number of LL is similar to the increase in LL that occurs when LL is cultured alone or with normal macrophages for the first 18 hr of culture (approximately one doubling of cells). To resolve this apparent paradox of increased cell number without DNA synthesis, the DNA content of LL cells that were cultured with activated macrophages for 16 hr was analyzed by flow microfluorometry. These experiments indicated that subsequent to co-culture with activated macrophages, LL cells with a 50% reduction in their normal DNA content could be detected. Furthermore, after a 2-hr incubation with colcemid a >95% reduction in metaphase cells occurred in LL cells cultured with activated macrophages. However, dividing nuclei without chromosome condensation appeared to be a prominent feature of these cultures. This would suggest that the genotypic or phenotypic program for cell division in the tumor cells is such that under these unique circumstances of tumor cell-activated macrophage interaction, a “reductive” cell division can proceed in the absence of DNA synthesis. We suggest that this aberrant division may be related to the lethal event that leads to activated macrophage-mediated tumor cell cytotoxicity.
Regulation of Immunoglobulin Biosynthesis in the Murine Plasmacytoma MOPC 315
Authors: Siebert Gary R. , Harris John F. , Gefter Malcolm L.
Published: December 2022

We have examined certain aspects of IgG biosynthesis by constructing hybrids between MPC11 (γ2b, κ) and MOPC 315 (α, λ2) that have lost the ability to synthesize one or the other heavy chain. Cells express the three chains in a stable fashion, and both autologous (parental) and heterologous (nonparental) H and L chain pairs form and are secreted. The α H chain was found in polymeric form when associated with the heterologous κ L chain. The λ2 L chain covalently assembled to the heterologous γ2b H chain. Surprisingly, autologous pairing was always favored over heterologous pairing in vivo by 5 to 10:1 in terms of rate of assembly. Similar ratios were maintained in the secreted protein. These results suggest that co-expression of particular H and L chain pairs is predetermined. Evolution presumably operates to improve antigen recognition as well as rate of assembly of active molecules.
Studies of Immunosuppression by Cobra Venom Factor
Authors: Martinelli Giorgio P. , Matsuda Takemasa , Osler Abraham G.
Published: December 2022

The immunosuppressive activity of CVF was evaluated in mice immunized with sheep erythrocytes and dinitrophenylated proteins. Serum antibody levels to these immunogens were estimated in activity units and on a weight basis for IgG. IgM as well as IgG antibody responses were diminished in mice pretreated with CVF. However when soluble immunogens were incorporated in CFA the suppressive effect associated with CVF was inapparent. It is suggested that C depletion per se may not fully account for the observed immunosuppression. The latter may result not only from the depression of C3 levels but also from the biologic activities of C cleavage products some of which modulate the secretory functions and state of activation of macrophages.
Functional Differentiation of B Lymphocytes in Agammaglobulinemia
Authors: Dosch Hans-Michael , Gelfand Erwin W.
Published: December 2022

The addition of fresh peripheral blood mononuclear cells (PBL) from four of seven patients with agammaglobulinemia to generated hemolytic plaque-forming cells (PFC) resulted in a dose-dependent suppression of PFC. This spontaneous suppressor cell activity (SSA) was restricted to the four patients who could generate a PFC response in vitro. SSA was mediated by a small subset of E-rosetting T lymphocytes characterized by theophylline-sensitive E-receptors and surface receptors for Fc-IgG. The effects of SSA were temperature dependent and reversible, and pokeweed mitogen could prevent the rapid decline of SSA observed during culture. Augmentation of SSA was achieved by agents known to increase intracellular levels of cyclic AMP, whereas lithium chloride abrogated SSA, including the drug-induced effects. Cells mediating SSA may play a role in preventing the normal transition of pre-B cells to B cells in patients with agammaglobulinemia without B lymphocytes.
Characterization of a Specific Adenosine Receptor on Human Lymphocytes
Authors: Marone Gianni , Plaut Marshall , Lichtenstein Lawrence M.
Published: December 2022

We have examined the mechanism of action of adenosine, a naturally occurring nucleoside that has profound effects on lymphocyte function. Adenosine (0.01 µM to 10 µM) increased lymphocyte cAMP levels in a dose-dependent fashion with a maximal (10 µM) increase of about 4-fold, whereas adenine, guanosine, and inosine had no effect on lymphocyte cAMP levels at concentrations of 100 µM. Adenosine appears to act on the cell surface since 1) 2-chloroadenosine, a poorly metabolized adenosine analogue, was as active as adenosine and 2) dipyridamole, which markedly inhibited [3H]-adenosine uptake by human lymphocytes, did not affect adenosine-induced accumulation of cAMP.

The specificity of the adenosine effect was established by showing that the methylxanthine derivatives, theophylline and 3-isobutyl-1-methylxanthine (IBMX), specifically block the accumulation of cAMP in lymphocytes induced by adenosine. Theophylline is a competitive inhibitor of the effect of adenosine, with an estimated dissociation constant of theophylline-receptor complex of about 6.3 × 10-7 M. The results suggest that adenosine increases the intracellular cAMP content of lymphocytes as a result of its interaction with a specific membrane receptor which results in the activation of adenylate cyclase.