OKT4 and OKT4A antibody treatment as immunosuppression for kidney transplantation in rhesus monkeys

A mixture of OKT4+4A monoclonal antibodies (reactive with T4 cells) was tested for its immunosuppressive potential in rhesus monkeys receiving a kidney allograft. The kidney transplant model used in this study was designed to mimic the clinical situation. Therefore, all animals received a low dose of azathioprine and prednisolone, and the effectiveness of monoclonal antibody treatment was assessed in nontransfused and transfused recipients. The treatment very effectively suppressed acute graft rejection in untransfused recipients. In transfused recipients, which show an improved graft survival, no additional favorable effect of OKT4 + 4A treatment was seen when this treatment was given at the time of transplantation. It is possible that transfused recipients that reject their kidney in an acute fashion do not benefit from the OKT4 + 4A treatment because they have generated primed effector cells that belong to a T4-negative subpopulation or a T4-positive subpopulation with high affinity for donor cells. When the OKT4 + 4A treatment was given at the time of graft rejection in transfused recipients, thus treating chronic rather than acute rejection, a modest improvement in graft survival was observed. It seems, therefore, that anti-T4 antibodies will be of limited value for clinical transplantation and should be used in combination with other immunosuppressive drugs.

Enumeration of (auto)antibody producing cells in human using the "spot-ELISA"

An enzyme-linked immunosorbent assay (spot-ELISA) for individual immunoglobulin secreting cells, which became recently available, was applied to the enumeration of human B lymphocytes secreting specific antibodies of thyroglobulin. Polyclonally activated B cells from patients with auto-immune thyroid disease are incubated in thyroglobulin coated plates. After removal of the cells specific antibodies are visualized by means of an immunoenzyme technique employing agarose to localize converted substrate. Individual specific antibody secreting cells are counted as blue spots using an inverted microscope. Numbers and isotype of spots correlate well with the amount and isotype of secreted antibody as detected with a conventional ELISA. This easy to perform, complement-independent technique offers a useful alternative to conventional plaque forming cell assays.

Effects of in vivo administration of monoclonal antibodies specific for human T cell subpopulations on the immune system in a rhesus monkey model

Monoclonal antibodies specific for human T cell subsets have been tested for their immunosuppressive effect in a rhesus monkey skin graft model. Rhesus monkeys were injected i.v. daily with antibodies specific for helper T cells (OKT4 and 4A), for cytotoxic/suppressor T cells (OKT8A), or all peripheral T cells (OKT11A), and they received an allogeneic skin graft one or two days after the initial antibody treatment. The OKT4, 4A, and 11A antibodies prolonged skin graft survival, but OKT8A did not. All animals were carefully monitored regarding levels of T cell subsets and antibody formation to the injected monoclonal antibody. The relevant T cell subset was not eliminated from the circulation when OKT4 and OKT4A antibodies were given separately. The OKT4+ cells remained in the circulation coated with antibody. OKT4+ cells could no longer be demonstrated when both OKT4 and 4A were given simultaneously. However, this difference in effect on the OKT4+ cells did not influence skin graft survival time. All animals receiving monoclonal antibody treatment developed antimouse-Ig antibodies after 10 to 13 days of treatment, which presumably counteracted the effect of the antibodies. From these data it appears that the rhesus monkey is a useful animal model in which to investigate the potential of monoclonal antibodies against human lymphocyte subpopulations to modify and regulate the immune response in an orderly fashion.

The effect of in vivo application of monoclonal antibodies specific for human cytotoxic T cells in rhesus monkeys

Rhesus monkeys were treated in vivo with monoclonal antibodies specific for human cytotoxic T cells. These antibodies reacted with rhesus lymphocytes as they do with human lymphocytes. Injection of a pool of monoclonal antibodies resulted in rapid elimination of the relevant T cell subpopulation from the circulation. Injection of a single monoclonal antibody did not result in elimination of the subpopulation, but the cells were coated with the injected monoclonal antibody. Injection of the single monoclonal antibody did not prolong the allogeneic skin graft. These results indicate that the rhesus monkey is a useful model for testing antihuman monoclonal antibodies.

Typing for RhLA-D in rhesus monkeys: II. Genetics of the D antigens and their association with DR antigens in a population of unrelated animals

A population of 94 unrelated rhesus monkeys was typed for MLC antigens using 38 homozygous typing cells which define RhLA-D specificities. A genetic analysis showed that the ten D specificities are alleles of a single locus, the gene frequencies of which are in Hardy-Weinberg equilibrium. The association between the cellularly defined D and the serologically defined DR antigens in the population was usually high, confirming the close relationship between D and DR antigens. Two new associations were found, i.e. between the D-locus antigens 9 and 10 and the serologically defined B-cell antigens 109 and 101, respectively. This observation confirms prior speculations that the latter two antigens may belong to the DR series.

Typing for RhLA-D in rhesus monkeys: I. Characteristics of ten groups of homozygous typing cells

Certain characteristics of 38 homozygous typing cell (TC's) of rhesus monkeys were determined. These TC's define ten RhLA-D locus specificities. Eight of them are associated with established RhLA-DR antigens. Two other groups of typing cells, D9 and D10, were previously considered to be associated with "blank" antigens of the DR series; they now appear to be associated with B-cell antigens which are also likely to be controlled by the DR locus. No influence of RhLA-A or B antigens of MLC reactivity was observed. It was shown, however, that products of at least one locus other than D/DR is responsible for MLC stimulation. Whether those MLC antigens are associated with serologically identifiable B-cell antigens which are not controlled by the DR locus, is not yet clear.

Acute bleeding varices: a five-year prospective evaluation of tamponade and sclerotherapy

In a five-year study of massive upper gastrointestinal hemorrhage, 143 patients had esophageal varices diagnosed on emergency endoscopic examination. Seventy-one patients had active bleeding from varices and required Sengstaken tube tamponade during at least one hospital admission. The remaining patients included 33 with variceal bleeding which had stopped and 39 who were bleeding from another source. Sixty-six of the former group of 71 patients were referred for emergency injection sclerotherapy. These 66 patients were followed prospectively to August 1980, and had 137 episodes of endoscopically proven variceal bleeding requiring Sengstaken tube control followed by injection sclerotherapy during 93 separate hospital admissions. Definitive control of hemorrhage was achieved in 95% the patients admitted to the hospital (single injection 70%; two or three injections 22%). The death rate per hospital admission was 28%. No patient died of continued variceal bleeding, and exsanguinating variceal hemorrhage no longer poses a major problem at our hospital. The combined use of initial Sengstaken tube tamponade followed by injection sclerotherapy has simplified emergency treatment in the group of patients who continue to bleed actively from esophageal varices, despite initial conservative treatment.

Mixed lymphocyte reactivity in chimpanzees. II. Family studies and identification of D locus antigens

A large number of related chimpanzees were tested in mixed lymphocyte cultures against each other. Several similarities among the D locus products coded for by different ChLA haplotypes were observed. Six animals were found to be homozygous for D locus antigens and two of these animals carried the same D specificity. Hence, the available "typing cells" permitted the identification of five D locus antigens of the chimpanzee. So far, no linkage disequilibrium has been found between any of the D locus antigens and ChLA-A or -B locus antigens.

Mixed lymphocyte reactivity in chimpanzees. I. Some technical and genetic aspects

One-way mixed lymphocyte culture (MLC) tests were performed among the members of five chimpanzee harems in all possible combinations: parents, parent-child, siblings and half-siblings. The technical aspects of MCL testing in chimpanzees appeared to be very similar to those observed for human and rhesus monkey MLC's. Two unexpected observations were made for which no satisfactory explanation can as yet be give: firstly, the occurrence of animals with consistently high autologous values and secondly, the existence of chimpanzees displaying low MLC responsive. The high autologous values occurred mostly in older imported animals (25% with high autologous values), while only one of the 45 laboratory born animals showed this phenomenon. Low responsiveness occurred in a few offspring belonging to a single harem only and is therefore likely to be genetically controlled but, as it appeared, not by genes linked to ChLA. Data suggesting the existence of an MHC-linked "major MLC" or D locus were confirmed and extended. A gene dose effect for D locus antigens was demonstratable, i.e., combinations of related animals differing for one showed lower MLC responses than combinations differing for two ChLA haplotypes. The number of D locus alleles was estimated to be 10.

HC restricted dual specific inhibition of mixed leukocyte culture reactions by human HLA antibody molecules

A human alloantiserum was found which selectively inhibits responding cells in mixed leukocyte culture reactions. Inhibition was achieved by pre-incubation of responder cells in the antiserum followed by washing. The serum showed dual specificity as an inhibiting agent. First, inhibition was restricted to HLA-B7 or -B40 positive stimulator cells, specificities against which the antiserum also had cytotoxic activity. Second, inhibition was almost exclusively associated with the presence of the phenotype HLA-A1, -B8 on the responder cells The HLA associated specificity for responder cells was unexpected since no alloantibody activity directed to responder alloantigens could be detected by conventional serological-methods. The antiserum donor had not been immunized with HLA-A1, -B8 antigens nor with known crossreactive antigens. Furthermore, the serum donor did not carry HLA-A1, -B8 antigens herself. The inhibiting substance in the antiserum had physicochemical properties of IgG and was specifically reactive with HLA-B7 positive platelets. Pepsin digest preparations were not inhibitory. Fc receptor positive responder cells were required for inhibition. Responder cells, preincubated with the antiserum, suppressed the response of cells not incubated with the antiserum. Three possible explanations of these results are discussed: specific binding of the Fc part of the antibody with Fc receptors of responder cells, specific activation of suppressor cells and cross-reactivity.

Possible mechanisms by which alloantisera inhibit in the MLC test

MLC inhibition studies were performed with two human alloantisera: one specific for HLA-B7, the other for HLA-DRw7. The stimulator cell inhibitory effects of these sera were tested in primary and secondary MLC tests. Both sera inhibited in the primary MLC, whereas only the anti-DRw7 serum was capable of blocking the secondary MLC test. The difference in inhibiting properties of these sera was further analyzed in primary MLC tests using selected MLC combinations, Fc receptor negative cell populations and pepsin digests of the anti-B7 serum. Anti-DRw7 antibodies could inhibit by masking the stimulatory DR antigens. The inhibition of the anit-B7 antiserum was dependent on Fc, which suggested that anti HLA-B antibodies inhibited by some other mechanism. This inhibition could have been caused by antibody dependent cellular lympholysis of the stimulator cells or by the induction of suppressor cell activity.

Inhibition of MLC stimulator function by antibodies directed to non-HLA antigens

The properties of five human alloantisera which inhibit the stimulating capacity of cells in an MLC reactions are described. All of the sera showed patterns of inhibition in families which did not correlate with HLA haplotypes. In a large proportion of the families investigated the sera did not react with parental cells but inhibited the cells from one or more of the children. Absorptions were performed with one of these sera using such non-reactive parental cells. Paternal cells absorbed out the inhibiting activity while maternal cells did not. This indicates that expression of the antigen with which the inhibiting antiserum reacts is insufficient for inhibition and other factors, either environmental or inherited from the mother, influence the capacity of the antiserum to cause inhibition. This antigen was most likely a non-HLA antigen.

Human skin grafts from mixed lymphocyte culture-positive donors provide help for the rapid rejection of simultaneously transplanted skin grafts from mixed lymphocyte culture-negative donors

The influence of grafting more than one skin transplant simultaneously on one recipient was investigated. When a mixed lymphocyte culture (MLC)-negative skin was transplanted along with an MLC-positive skin, the MLC-negative skin survived for a significantly shorter time than when transplanted alone. This indicated that the MLC-positive skin provided a stimulus that could provide help to reject the MLC-negative skin. This finding might be important clinically. When an MLC-negative transplant is given to a patient, one should not transfuse this patient with MLC-positive leukocyte-rich blood.

Influence of previous immunization on skin graft survival

The results of skin grafts transplanted in immunized and nonimmunized recipients was analysed. Specific sensitization for HLA-A or B determinants shortens graft survival if the recipients were immunized by s.c. injections of leukocytes. When the recipients had been pregnant, no such influence of specific HLA-A or B sensitization could be demonstrated. The variance in mean survival times of grafts exchanged between mixed lymphocyte culture (MLC)-positive donor-recipient combinations was significantly smaller than the variance in mean survival time (MST) of grafts exchanged between MLC-negative combinations. This difference could be the result of the influence of allograft immune-activating determinants of different strength in the MLC-negative donor-recipient combinations. Also the variance in MST of grafts in immunized recipients was significantly larger than the variance in MST of grafts in nonimmunized recipients. Apart from the obvious effect of HLA-A and B sensitization, other less well documented factors must have influenced graft survival. We did not find evidence for a graft enhancing effect of B cell-specific antibodies.

Influence of matching for HLA-DR antigens on skin graft survival

HLA-DR typing results of 47 skin transplant donor-recipient pairs were analysed. HLA-A, B, and C typing and mixed lymphocyte culture (MLC) testing was also included in this study. Skin transplants exchanged between HLA-A-, B-, and DR-identical, MLC-negative donor-recipient pairs had the longest graft survival (mean survival time, 17 days), whereas skin grafts exchanged between completely nonidentical donor-recipient combinations had the shortest survival (mean survival time, 10 days). Because of the correlation between identity for the DR antigens and the low or nonreactivity in the MLC test, identity for DR will predict a better skin graft survival than nonidentity. It was concluded that the best match between donor and recipient of a graft, using only serological techniques, is one where there is identity for HLA-A, B, and DR.

Can anti HLA-A and -B antibodies inhibit the MLC test?

Eleven lymphocytotoxic pregnancy sera were tested for inhibition in the MLC test. Responder inhibition and stimulator inhibition were analyzed separately by using cells from the serum producer as stimulator and responder respectively. Only three sera showed inhibitionof responder function, whereas all sera showed inhibition of stimulator function. The specificity of the latter inhibition was at least in part attributable to antibodies directed to specificities other than B-cell specificities (presumed to be coded for in the HLA-D region). This was deduced from the fact that platelet eluates devoid of anti B-cell antibodies effectively inhibited in MLC.

Inhibition of the mixed leukocyte reaction by alloantisera in man. II. Incidence and characteristics of MLC-inhibiting antisera from multiparous women

The incidence of MLC-inhibiting antibodies was determined in 42 pregnancy sera. MLC's were carried out between the cells from the serum donor and her husband in the presence of nonimmune AB serum and the test serum. Fifty per cent of the sera reduced the MLC response to less than 40% of the control values. Only four sera had lymphocytotoxic activity. The inhibition was strong against the specific immunizor, less strong against random unrelated cells and weak against cells which were SD-identical with the serum donor. Absorptions with lymphocytes and platelets were carried out. Lymphocytes removed activity in three of the four sera tested. Platelets removed activity from one serum. It was concluded that both anti-LD and anti-SD antibodies were able to inhibit the MLR at the stimulator cell level.

Inhibition of the mixed leukocyte reaction by alloantisera in man. I. Technical aspects

Some technical aspects of MLC inhibition by sera obtained from multiparous women were studied. The variability of the MLC response was very high. The serum source used in the cultures was probably to a large extent responsible for this variability. Aspecific inhibition, which was observed with some test sera, could be removed by dialysis against PBS. To make the evaluation of inhibition by immune sera objective, a scoring system was introduced for the degree of inhibition. Test sera were usually added to the cultures. Alternatively, stimulator and responder cells were preincubated with the test serum. Preincubation of the stimulator cells did not show a difference in inhibition pattern when this was compared with serum addition. Preincubation of the responder cells showed a completely different inhibition pattern. The MLC inhibition test compared very well with an indirect immunofluorescence test and a cytotoxicity test using B-cell enriched cell suspensions.