Relationship between beta2-microglobulin and cell-surface alloantigens of the mouse

Molecular relationships between beta2m and other cell surface antigens (H-2, Tla, Ia, and Thy-1) were studied with the double immunofluorescence method. Cells were incubated with an antiserum against one antigen capped, and then tested with an antiserum against a second antigen. Capping of beta2m on thymocytes led to simultaneous capping of H-2 and Tla but not Thy-1 antigens; capping of H-2 and TIa (but not Thy-1) antigens resulted in capping of all beta2m detectable by the immunofluorescence method. Similarly, capping of beta2m on B or T lymphocytes resulted in capping of H-2 and vice versa. Ia antigens on B lymphocytes were not capped after the redistribution of beta2m. We conclude from these data that, in the cell membrane of thymocytes, virtually all the beta2m molecules are associated with H-2 and Tla, but not with Thy-1, and that on the cell surface of T or B lymphocytes, virtually all beta2m is associated with H-2 but not with Ia. We found no evidence of any significant free beta2m on either thymocytes or splenocytes.

Specific lysis of human colon tumor cells by antibodies to CEA and isoantigen A: dependence on rabbit serum or neuraminidase

The 51Cr cytotoxicity test was used to measure specific antibody reactions against carcinoembryonic antigen (CEA) and isoantigen A on the surface of human colon tumor cells. When human serum or guinea pig serum was used as a source of complement, no anti-CEA or anti-isoantigen A cytotoxicity was demonstrable despite binding of specific antibodies and activation of complement at least through the C3 component on the cell surface. In contrast, specific anti-CEA and anti-isoantigen A cytotoxicity was demonstrated when rabbit serum was used as a source of complement. Specific antibody-mediated cell lysis was also achieved with guinea pig complement if the cells were treated with neuraminidase before testing. These results support the concept that certain tumor cells have surface properties that render them resistant to immune lysis.

Mitigation of Graft-versus-host disease in mice with xenogeneic antithymocyte serum and complement

In vitro treatment of parental C57BL/6 lymphohematopoietic cell grafts with unabsorbed guinea pig anti-mouse thymocyte serum (ATS) and guinea pig complement (GPC), prior to inoculation into lethally irradiated B6D2F hybrid hosts, has proven to be of value in terms of mitigating graft-versus-host disease (GvHD). However, the beneficial effect of such a pregrafting procedure is limited to the prevention of acute GvHD. The late GvHD remains a continuing problem, and is probably due to the graft-versus-host activity (GvHA) of newly produced nontolerant lymphocytes from lymphoid precursors resistant to ATS. Possible ways to render these precursors sensitive to ATS and complement are discussed. The potential significance of thymic hormones and cyclic AMP in achieving this is emphasized.

[Anti-thrombocyte antibodies]

1. There are two possible ways in which platelets may be involved in immune reactions: a) as target cells for antiplatelet antibodies, and b) as receptor cells for circulating antigen-antibody complexes. Since most of the clinical tests used to detect "antiplatelet antibodies" are incapable of discriminating between the two mechanisms, thrombocytopenia in many autoimmune diseases with "antiplatelet antibodies" may well be caused by immune complexes. 2. Immune reactions involving platelets do not always lead to thrombocytopenia. A moderate acceleration of platelet destruction can easily be compensated by increased production: this situation corresponds to a "compensated thrombocytolytic state". Evidence is also presented for immunologically induced functional platelet defects of "immunologic thrombocytopathy.

Mutant lines of guinea pig L2C leukemia. II. Comparative cytogenetic studies and banding analyses of normal and leukemic karyotypes

Chromosomes of normal guinea pig (strain 2) cells and of cell lines dervied from a spontaneously arising leukemia were analyzed in detail. All cell lines studied, LG-L2C, GH-L2-C, BZ-LC, and EN-L2C, contained one M1 marker and two X chromosomes, in addition to other chromosome abnormalities specific for each cell line. The presence of the M1 marker and the two X chromosomes confirmed that all of these leukemic cell lines are derived from one ancestral line. Comparison of the chromosome markers and immunologic characteristics of these lines revealed that possibly the gene involved in the determination of C3 receptor sites is located on the terminal portion of the long arm of chromosome No. 2, but no other correlations could be made.

[Isoimmune antibody formation after blood transfusions]

During February 1973 to October 1974 950 inpatients of the Department of Surgery, Erlangen, were tested for the presence of iso-antibodies before and after blood transfusions. Irregular antibodies were demonstrable in 0.95% of the patients before they received a blood transfusion. In 2.73% of the cases blood transfusion resulted in sensitization with the formation of specific blood group antibodies. Identification of the 26 iso-antibodies showed a prevalence of anti-Kell and anti-E (7 cases each). In view of the frequent occurrence of these two antigens tests for their presence are advisable before a blood transfusion is given. Persons who are re-admitted to hospital should also be tested to the presence of irregular antibodies to ensure that sensitization has not occurred during the intervening period.

Characteristics of JMV Marek's disease tumor: a nonproductively infected transplantable cell lacking in rescuable Virus

Cells of the JMV Marek's disease (MD) tumor, originally produced by rapid serial passage of MD lymphoma cells in chickens, were characterized to determine whether they were of host or donor origin and to ascertain certain virus-host cell interrelationships. Differences noted in blood group B surface alloantigens between tumor cells and host lymphocytes indicated a probable nonhost origin (i.e., transplantability) of the tumor. JMV spleen tumors contained predominantly large lymphoblasts bearing MD tumor-associated surface antigen. DNA from JMV tumor cell suspensions hybridized significantly with MD virus cRNA, which indicated that JMV cells contained at least a portion of the MD virus genome. No MD virus was rescued from JMV tumors by techniques suitable for rescue of virus from MD lymphomas. The JMV tumor cells were also devoid of MD virus-specific antigens. These properties differed markedly from those of MD lymphoma cells and make the JMV tumor cell a unique, potentially valuable, tool for further study of oncogenic herpesvirus infection and tumor immunity in the chicken.

"Physiological interaction" does not explain the H-2 requirement for recognition of virus-infected cells by cytotoxic T cells

B10.A (H-2Kk, H-2Dd) ectromelia-immune T cells from secondary responses in vitro were protent killers of both infected L929 (H-2Kk H-2Dk) and infected P-815 (H-2Kd, H-2Db) target cells. Specific competition with unlabelled targets showed that two separate T cell subsets were responsible for lysis of infected L929 and infected P-815 cells. One hypothesis to account for this (a form of "physiological interaction") is that T cells which kill one target e.g. infected L929) display only one out of two possible self-complementary recognition structures, in this example the H-2Kk alloantigen, not H-2Dd, whereas T cells that lyse infected P-815 targets display only H-2Dd, not H-2Kk. This hypothesis was tested and seems untenable because of the following results: A.TH (H-2Ks, H-2Dd) ectromelia-immune, secondary cytotoxic T cells which killed infected SJL/J (H-2Ks, H-2Ds) targets were themselves inactivated by pre-incubation with SJL/J cytotoxic T cells generated in one-way mixed lymphocyte reaction (MLR) against BALB/c (H-2Kd, H-2Dd). A.TL (H-2Ks, H-2Dd) ectromelia-immune secondary cytotoxic T cells which killed infected BALB/c targets were themselves inactivated by BALB/c cytotoxic T cells generated in MLR against SJL/J. Thus, virus-immune T cells which lyse infected targets by virtue of shared H-2K are also displaying H-2D alloantigen, and vice versa.

Immunologic cross-reactions between the specifically localizing cells (SLC) generated in response to sheep RBC and the red cells of other species

Some of the lymphoid cells selectively incorporating radioactive thymidine 3 days after primary immunization with SRBC which are capable of specifically localizing in the lymph nodes of adoptively immunized syngeneic recipients challenged with SRBC (SLC-SRBC)2 are also capable of specifically localizing in lymph nodes challenged with the red blood cells of a varieth of other mammalian species. The one nonmammalian RBC tested, CRBC, failed to cross-react with SRBC by this parameter even qualitatively, although it remains possible that a feeble cross-reaction might be demonstrated with large enough experimental groups. As expected, the magnitude of the observed cross-reactions seems to vary inversely with the phylogenetic distance between the species, with ORBC showing the strongest cross-reaction (41 to 49%), ARBC showing the weakest (8 to 13%), and BRBC and HRBC occupying intermediate positions (13 to 20%). Cross-reaction between secondary anti-SRBC antibodies and the red cells of the other species were weak and inconstant, suggesting that the observed cross-reactions of specific localization may involve T cells more than B cells. During the course of these studies, it was also possible to verify experimentally our impression that with existing methods of selectively labeling SLC it is possible to study the phenomenon of specific localization using only one population of labeled cells, providing certain essential controls are employed.

Multiple sclerosis and high incidence of a B lymphocyte antigen

Multiple sclerosis patients were tested for six new antigens present on human B lymphocytes. The group 4 specificity occurred in 83.9% of the 56 patients as compared to 32.5 percent in 72 healthy controls (P less than .003). The antiserums defining the five other B lymphocyte specificities reacted at a lower frequency to B cells from multiple sclerosis patients, showing that increased reactivity to group 4 antiserum was specific. Linkage of a hypothesized multiple sclerosis susceptibility gene with certain haplotypes of HLA-A3, HLA-B7 HLA-DW2, and the new B group 4 can be inferred.

Secretion of Ia antigens by a subpopulation of T cells which are Ly-1+, Ly-2-, and Ia-

It was found that Ia antignes are rapidly secreted by a subpopulation of splenic T lymphocytes which are nonadherent and which express the surface phenotype Ly-1+, Ly-2-, and Ia-. Secretion of the Ia antigens was a metabolically active process which was inhibited by sodium azide and by Pactamycin, an inhibitor of protein synthesis.

Control of the immune response: role of macrophages in regulation of antibody-and cell-mediated immune responses

The ability of peritoneal macrophage subpopulations, separated into different classes according to their size, to reconstitute antibody or cellular immune responses in macrophage-depleted spleen cells has been investigated. Data are presented to show that whether reconstitution is by "normal" or "activated" macrophages, be they syngeneic or allogeneic to the lymphocyte source, different populations reconstitute antibody and cellular immunity. Reconstitution is in general by two classes of macrophages, small and large. The former seem to reconstitute only if syngeneic to the responding lymphocyte pool, whereas large macrophages reconstitute immune responses from allogeneic lymphocytes as well as syngeneic lymphocytes. Evidence is also presented to show that syngeneic large macrophages can determine the type of immune response reconstituted; that is, with greater numbers of large cells only cytotoxic responses (and not T-dependent antibody formation) were reconstituted and vice versa.

A membrane antigen common to human cancer and fetal brain tissues

Membrane antigens of a cultured human melanoma line, UCLASO-M14, were studied using immune adherence techniques. Allogeneic sera from melanoma patients that were reactive with the M14 but nonreactive with lymphoid cells of the M14 donor were used as antibodies. The antigen responsible for the reaction between M14 and the antibodies was searched for in other cancer, normal, and fetal tissues using antibody absorption techniques. The antigen was found in a variety of different histological types of biopsied and cultured cancer cells as well as in melanomas. The antigen did not exist in biopsied normal tissues, but it appeared in cultured normal skin and muscle. Neither normal lymphocytes nor cultured lymphoid cells showed any antigenicity. The antigen was present in human fetal tissues and was the strongest in fetal brain tissues at 22 weeks of development. Liver, spleen, thymus, and small intestine from the same fetus were negative for antigen.

A new I subregion (I-J) marked by a locus (Ia-4) controlling surface determinants on suppressor T lymphocytes

In an accompanying publication we show that a subpopulation of T lymphocytes, which includes allotype suppressor T cells, selectively expresses I-region determinants. In this report, we show that these determinants are controlled by a new locus, Ia-4. Unlike the classically defined Ia antigens, they are not found on B lymphocytes. Antibody against Ia-4 determinants cannot be detected by conventional dye exclusion cytoxicity assays, suggesting that they are present on a small subpopulation (less than 10%) of peripheral T lymphocytes. The Ia-4 locus marks a new I subregion, provisionally designated I-J. This chromosomal segment is defined by the crossover positions in strains B10.A(5R) (K-end boundary) and B10.HTT (D-end boundary), and maps between the I-B and I-C subregions.

Selective expression of H-2 (i-region) loci controlling determinants on helper and suppressor T lymphocytes

Data presented here show that locidentify in the I-region of the H-2 gene complex are selectively expressed in different functional T-cell subpopulations. These loci are closely linked (or possibly identical) to loci that control immune responses. They control surface determinants which identify helper and suppressor T lymphocytes. Determinants described here on allotype suppressor T cells (Ts) are found on normal (nonsuppressed) lymphoid cells, but are not found on helper T cells (Th). These determinants are controlled by a locus mapping in the I region of the H-2 complex. In an accompanying publication we show that this locus (Ia-4) marks a new I subregion (I-J) and is expressed only on T cells. Thus Ia-4 determinants idenfity a T-cell subpopulation which includes Ts but not Th. Th also carry identifying surface determinants controlled by loci that map to the H-2 complex, probably within the I region. These determinants are not found on Ts. Data presented also establish that loci in the I region control determinants on Th, but do not conclusively demonstrate that these are the determinants that distinguish Th from Ts. The selective expression of H-2-controlled determinants on Ts and Th suggests that these determinants are directly involved in immunoregulation.

Influence of H-2 on the ontogenesis of a spleen cell population which lacks C3 receptors and Thy-1 antigen

During ontogeny there are marked differences in the cellularity of the spleen of mice from different inbred strains. Data from segregation analysis demonstrate that one of the genes involved in the control of the size of the spleen at 15 days lies in the H-2 region. In contrast to previous reports, we find that the cell population under H-2 influence lacks complement receptors.

Immunity to tumor antigens: potential implications in human neuroblastoma

Immune reactions to tumor-specific and tumor-associated antigens have been demonstrated in animals with neoplasms with in vitro and in vovo techniques. Some of the antigens detected in vitro induce transplantation resistance in vivo, while others do not. Human neuroblastoma cells cultivated in vitro have been shown to possess common antigens to which lymphocytes from neuroblastoma patients react. Whether it is possible to augment the immune reactivity of patients with neuroblastoma to these common antigens and, if so, whether this heightened immune reactivity would have clinically beneficial effects are as yet unknown. These reactions are complex, involving both cellular and humoral mechanisms. The fact that one type of immune response can be detected to one type of antigen present in a tumor in vitro does not necessarily mean that the immune response is effective in vivo. Responses to other tumor antigens may be deficient, or the immune response may be depressed. This may be due to active suppression of and/or selective deficiencies in critical cell populations required for an augmented immune response; this possibility may be evaluated with techniques allowing for in vitro sensitization to tumor antigens.

Expression of Ia antigens on hapten-specific B cells. I. Delineation of B-cell subpopulations

The nonimmune adult spleen contains at least two B-cell subpopulations. The majority of primary B cells express cell surface Ia determinants and have the capacity to give rise to IgG antibody-producing clones after T-cell dependent antigenic stimulation. There is also a small subpopulation of primary B cells which are, by definition, Ia negative, since their activity is not eliminated by negative selection with anti-Ia serum and complement. The Ia-negative B cells give rise to clones that produce only IgM antibody. These B-cell subsets may form a continuum in B-cell maturation, or they may exist as discrete B-cell lineages. Since the cellular expression of Ia antigens appears to correlate with the ability of the B cell to generate IgG-producing clones, it is speculated that Ia molecules may have a role in the IgM to IgG B-cell switch mechanism.

The evolution of genes in the major histocompatibility complex

The mammalian major histocompatibility system (MHS) includes genes determining the structure of the classical major transplantation antigens (H-2K and H-2D), the I region-associated (Ia) antigens, and genes determining the structure level or both of the first four components of complement. In addition, the I region incudes a series of genes determining specific immune responsiveness to a wide variety of antigens - the Ir genes. The available evidence indicates that the K, D, and I gene products are cell surface glycoproteins that are structurally and perhaps functionally related. The multiple genes in this complex region apparently arose by a process of tandem gene duplication. There is some reason to believe that the murine MHS may have originated from genes in the T/t complex - a "supergene" near the centromere of the 17th mouse chromosome determining a series of steps in early embryonic development. Other evidence has led to the postulate that genes in the MHS have given rise to immunoglobulin structural genes by a process of translocation and further gene duplication. While these evolutionary relationships are speculative, it seems clear that the MHS determines a series of cell surface proteins that are intimately involved in cellular recognition and interaction, and in regulation of immune responsiveness by a new, nonimmunoglobulin recognition system.