D. Bernard Amos

Hu-1: Major histocompatibility locus in man.

A single locus with 15 or more alleles controls reactivity in mixed leukocyte culture tests. Genes at this locus also control most of the specificities measured by cytotoxic antiserums to leukocytes. Both of these tests can be used to predict survival of skin grafts. It is proposed that this is the major histocompatibility locus in man.

A mathematical analysis of human leukocyte antigen serology

Abstract This paper presents and explores a comprehensive mathematical model for human leukocyte antigen serology, based on a mathematical formalization of the concept of specificity. This model is general enough to take into account such factors as absorption, elution, cross-reactivity, and incomplete immunization. The paper includes a presentation of the relevant immunological background and a short discussion of the underlying computational difficulty of the basic problems. Upper and lower bounds are derived for the minimal number of specificities required to explain a given set of HLA reactions, and it is shown that the numbers of antibodies and antigens involved must be no less then this minimal number of specificities. Other techniques and theorems are also presented to aid in reducing and analyzing HLA reaction matrices.

POSSIBLE RELATIONSHIPS BETWEEN THE CYTOTOXIC EFFECTS OF ISOANTIBODY AND HOST CELL FUNCTION

Antibodies usually can be detected in the serum of mice that have recently rejected a homograft. This reversal of the findings of an earlier generation is now well substantiated and has been accomplished chiefly through persistent efforts to improve the methods available for antibody For many years there was doubt as to the existence of such isoantibodies; interest has now shifted to discussion of the significance of the antibodies formed, their functional relationship to the host cells found in proximity to the graft, and to the differences between humoral antibody and hypothetical cell-bound antibodies. Resolution of many of the problems concerning the relationship between host cells and antibody during graft rejection is difficult because lymph node and spleen cells (the usual sources of immune cells in transplantation experiments) liberate circulating antibody; there is therefore some uncertainty as to what each component is doing. Transfer of large quantities of regional lymph nodes to a nonimmune animal confers a state of immunity almost as complex as that existing in the originally immunized host? Winn’s modification of the technique whereby immune cells are mixed directly with the tumor suspension before injection has already given further quantitative information! I t is probable that further experiments of this nature will resolve a number of questions raised by the earlier experiments of Mitchison’ (see also Gorerg) . While recognizing that the reactions occurring during graft rejection involve a variable number of components and that these components must interact, sometimes synergically and sometimes antagonistically, it seems logical to simplify the system as far as is practicable. Humoral antibody can be separated readily from cells, whereas it is difficult to obtain cells free from antibody. Antibody activity therefore has been defined with greater precision. This paper surveys the increasing evidence for antibody participation in homograft rejection, discusses some observed anomalies of both antibody and immune cell activity, and presents a hypothesis to explain why antibody, complement, immune cells, enzymes, and enzyme inhibitors may all be interdependent. Antibody activity was clearly demonstrated against homografts in rats by LumsdenloJ1 (see also the review by Moppett12). Criticism by Ludford13 and by Phelpsl* largely obscured the significance of much of Lumsden’s excellent work, and the overenthusiasm of his conclusions helped to push his work into obscurity. Gorer painstakingly re-established the validity of many of Lumsden’s ideas and found, first in rabbits and then in

Incompatible Bone-Marrow Transplantation in Lymphopenic Immunologic Deficiency

Abstract Immunologic enhancement was employed to circumvent fatal acute graft-versus-host disease after incompatible bone-marrow transplants given an infant with severe combined immunodeficiency. Maternal plasma contained lymphocytotoxic antibodies to paternal and patient lymphocytes and blocked mixed leukocyte responsiveness of maternal cells against mitomycin-C-treated paternal or patient cells. The infant was treated with maternal plasma before and after infusions of 5 X 106 per kilogram of maternal bone-marrow cells on two occasions. After each cell infusion dramatic weight gain and resolution of infections occurred. Improved immunologic capacity was manifested by development of delayed cutaneous responsiveness to candida antigen from the 13th day after transplant and later rises in serum IgG, IgA, and IgM concentrations; immunologic capacity was not increased by implantation of a fetal thymus nine months later. This infants survival for 14 months after transplant, the longest known among patients wi...

A public HLA antigen associated with HLA-A9, Aw32, and Bw4.

TheHLA complex codes for three distinct 44000 dalton molecules associated withΒ2 microglobulin — HLA-A, B and C —each with its own multiallelic series of private antigens. The HLA-B molecule is exceptional in that it also carries a diallelic system,Bw4 andBw6. One of these,Bw4, is often associated with the A- locus specificity A9. This finding has usually been ascribed to linkage disequilibrium between A-and B-locus antigens. We have shown, however, that an epitope called LHe is actually shared by A-locus and B-locus molecules. This epitope is found on all HLA-B molecules bearing the Bw4 determinant and is also found on all HLA-A molecules carrying the A9 (Aw23 and Aw24) or Aw32 specificities. We consider this a “public” HLA antigen; the possible molecular basis for both subtypic and public antigens on a single glycoprotein is discussed.

Lymphocyte-mediated cytolysis of allogeneic tumor cells in vitro: I. Search for target antigens in subcellular fractions

Abstract To analyze the nature of the target cell determinants recognized and bound by killer lymphocytes during lymphocyte-mediated cytolysis (LMC), the specific binding of serologically active tumor cell membrane fractions to cytotoxic T lymphocytes has been investigated. Particulate membrane fractions and soluble antigen preparations (extracted by papain or 3 M KCl) from tumor target cells were tested for their ability to inhibit the destruction of intact 51 Cr-labeled target cells by killer lymphocytes in vitro . The effect of papain-solubilized tumor cell antigen on the binding of killer lymphocytes to tumor cell monolayers was also evaluated. Direct assays to determine the extent of binding of unlabeled or radioiodinated soluble antigen (extracted by papain or deoxycholate) to cytotoxic lymphocytes were carried out. In marked contrast to their serological activity, all of these particulate and soluble preparations failed to inhibit LMC or bind to killer lymphocytes in an immunologically specific way. It is suggested that killer lymphocytes recognize and bind to an antigenic complex whose organization is dependent upon the integrity of the target cell membrane.

Characterization of human chemotactic lymphokine production induced by mitogens and mixed leukocyte reactions using a new microassay

Quantification of lymphokine production in vitro can be a useful tool in the evaluation of delayed hypersensitivity in various disease states. A micro-method for the measurement of chemotactic lymphokine production by human mononuclear leukocytes (MNLs) has been developed. MNLs are isolated on Ficoll-Hypaque gradients and cultured without plasma in microtiter plates. Culture supernatants are harvested through glass fibre filter paper under vacuum in a semi-automatic harvester. Chemotactic lymphokine activity in the supernatants is quantified in miniaturized Boyden chambers using human monocytes as responder cells. The production of chemotactic activity can be initiated by mixed leukocyte reactions as well as by soluble antigens or mitogens, and therefore may be a useful adjunct in tissue typing. Studies of lymphokine production in normal individuals indicate that these methods are quantitative, reproducible, and readily applicable to the study of this parameter of immune function in human disease.

Mechanism of lymphocyte-mediated cytolysis. The lmc cycle and its role in transplantation immunity.

The monograph in which this article appears is devoted to considerations of cellular immunity. We wish to restrict our contribution to a discussion of our own findings in both in vivo and in vitro studies and how we believe our observations contribute to an understanding of the mechanism of action of the sensitized lymphocyte against its target. We also wish to discuss some theoretical concepts of lymphocyte receptors and to introduce a new hypothesis to account for the cytotoxic mechanism(s) in lymphocyte-mediated cytolysis (LMC).

The Complement-binding And Absorptive Capacity Of Human White Blood Cells Treated With Neuraminidase1

Human lymphocytes treated with Vibrio cholerae neuraminidase (VCN) are more susceptible to cytotoxic human alloantisera than are sham treated cells. Sera from most normal or immunized donors showing no detectable anti-HL-A activity gave strong positive reactions with almost all VCN-treated isologous or autologous lymphocytes. Less than 10% of the sera tested were unreactive against all VCN-treated cells. Family studies utilizing VCN-treated lymphocytes have revealed patterns of antigens that segregate independently from HL-A. The absorptive capacity of both VCN-treated and sham treated leukocytes for cytotoxic human alloantiserum is dependent on the class (reaction strength) of the ceEs used. Although VCN treatment does not affect the hierarchy of cell classes, which is based on HL-A reactions, VCN-treated cells absorb more antibody activity than sham treated cells. Absorption of a serum sample with sham treated leukocytes removed HL-A-related activity as detected by a panel of sham treated cells, but left antibody activity against VCN-treated cells. All detectable cytotoxic reactivity of sera against normal or VCN-treated lymphocytes was lost upon substitution of C6-defi-cient or cobra venom-treated rabbit serum for the routinely used complement source.SUMMARYHuman lymphocytes treated with Vibrio cholerae neuraminidase (VCN) are more susceptible to cytotoxic human alloantisera than are sham treated cells. Sera from most normal or immunized donors showing no detectable anti-HL-A activity gave strong positive reactions with almost all VCN-treated is

HLA-DR7-Specific monoclonal antibodies and a chimpanzee anti-DR7 serum detect different epitopes on the same molecule

We describe here two monoclonal antibodies with HLA-DR7 serologic specificity. The antibodies, SFR16-DR7M, a cytotoxic rat IgM antibody of high affinity, and SFR16-DR7G, a noncytotoxic antibody of the rat IgG 2a class, react with only DR7-positive cells in radioimmunoassay. The cytotoxic activity of SFR16-DR7M correlates completely with the presence of the DR7 specificity, and segregates with the DR7-bearing haplotype in a family. SFR16-DR7M precipitates a class II molecule with the electrophoretic characteristics of DR molecules from LG-10, an HLA-DR7 homozygous cell line. SFR16-DR7G completely inhibits the cytotoxicity of SFR16-DR7M, but only partially inhibits the cytotoxicity of a chimpanzee antiserum with DR7 specificity, Gay/Swei. In binding-inhibition studies, binding of SFR16-DR7M to LG-10 cells is only partially inhibited by the chimpanzee antiserum and vice versa. Both SFR16-DR7M and Gay/Swei reciprocally deplete the same class II molecules from a 35S-methionine-labeled detergent-solubilized membrane preparation of the LG-10 cell line. The chimpanzee serum Gay contains antibodies reactive with epitopes on separated DR7 beta chains, while both SFR16-DR7M and SFR16-DR7G bind only to DR7 alpha-beta complexes. These data suggest that at least two allogeneic epitopes exist which result in the same serologic specificity, and that these epitopes differ in their requirement for alpha-beta complex formation.