D. Nelken

Effect of normal immunosuppressive protein (nip) on tumor growth in mice.

Abstract The effect of normal immunosuppressive protein on the take and growth rate of a methylcholanthrene-induced tumor in C 57 B 1 mice is described. NIP given in two injections ( 10 mg each), 24 hr before and 24 hr after tumor inoculation caused: (a) Enhanced tumor growth, most significantly observed at earlier stages after tumor inoculation, (b) Appearance of tumors in 25% of mice inoculated with only 10 3 cells, and in 100% of mice inoculated with 10 4 cells. Under similar conditions, in control groups no tumor takes could be observed in mice receiving 10 3 or 10 4 tumor cells.

Studies on Platelet Antigens

The presence of Rh‐Hr antigens in human blood platelets has been investigated by the following methods: direct agglutination, adsorption of anti‐Rh sera, elution experiments, mixed erythrocyte‐thrombocyte agglutination, direct and indirect antiglobulin tests, antiglobulin consumption and adsorption of isotopically labelled anti‐Rh sera.

Adjuvant-induced nonspecific suppressor cells: In vitro and in vivo studies

Abstract The in vitro mitogen responses of spleen cells from mice injected ip with the nonantigenic adjuvant, Al(OH) 3 , are markedly depressed. This depressed reactivity was found to be mediated by a population of nylon wool adherent, Fc-receptor-bearing suppressor cells. Suppressor cells were detected only in the spleens of the adjuvant-treated mice, as the response of lymph node cells to mitogenic stimulation in vitro was found comparable to that of normal controls. Moreover, elevated levels of suppressive activity could be detected in sera of Al(OH) 3 -treated mice during the first week after adjuvant administration, which, however, did not correlate with either the long-lasting presence of suppressor cells or the in vivo normal immune response of the adjuvant-treated animals. Studies designed to test the effect of suppressor cells on the generation of splenic PFC in vivo revealed that both the direct and indirect PFC responses against SRBC inoculated iv were enhanced rather than suppressed, as compared to those of the normal controls. Furthermore, the level of cytotoxic lymphocytes generated in spleens of Al(OH) 3 -treated mice immunized with allogeneic tumor cells was equal to or higher than that of the normal controls. In view of the present results, we feel that the concept that splenic, nonspecific suppressor cells (macrophages) are immunosuppressive in vivo as well as the in vivo relevance of in vitro findings should be carefully reevaluated.

Differential expression of HLA class-I antigens on B and T lymphocytes obtained from human lymphoid tissues

The amount of HLA class-I antigens was determined on the surface of enriched populations of B and T lymphocytes obtained from human peripheral blood, lymph nodes and spleens. The assays were performed using monoclonal antibodies that recognize different determinants on HLA class-I antigens and utilizing a simple and sensitive enzyme-linked immunosorbent assay (ELISA). Our results indicate that B lymphocytes obtained from human peripheral blood, lymph nodes and spleens express at least twice as many HLA class-I antigens as T lymphocytes obtained from the same organs.

Enzyme-linked immunosorbent assay for HLA determination on fresh and dried lymphocytes

HLA-A and -B antigens were detected on fresh and dried peripheral blood lymphocytes by an enzyme-linked immunosorbent assay. Intact cells fixed to plates with glutaraldehyde were used as antigen and anti-HLA alloantisera as a source of antibodies. Determination of HLA antigens by the ELISA technique was comparable with the complement-dependent cytotoxicity test. The relative stability of HLA antigens as shown in this report and the extensive polymorphism of the HLA system make the ELISA technique a promising tool for the analysis of HLA antigens on non-living cells including, for example, medicolegal investigation of blood stains.

False Positive Anti Human Globulin Tests Caused by Reticulocytes

False positive direct antiglobulin tests were caused by the interaction of reticulocytes with antiglobulin serum. Absorption studies revealed that the agglutination of reticulocytes in Coombs serum has no relation to the activity of the serum against antibody coated cells.

Inhibitory effect of alpha-globulin on the second set allograft reaction.

Summary α-Globulin fraction prepared from normal human plasma suppressed first as well as second set skin allograft reactions in rats. Spleen cells taken from mice, immunized by transplantation of skin allografts, and incubated with the α-globulin fraction failed to transfer transplantation immunity to isologous recipients. No evidence was obtained for cytotoxicity of α-globulin. Since human serum albumin failed to suppress immune response the mode of action of α-globulin was not considered to be due to antigenic competition.

A Two‐Stage Agglutination Test for the Detection of Antithrombocyte Antibodies

Abstract. A two‐stage agglutination test is described, in which the synergistie action of autoantibodies and heteroantibodies in subagglutinating doses is utilized for the detection of thrombocyte autoantibodies. The test is more sensitive than the direct agglutination test for detecting thrombocyte agglutinins. It also detects ‘incomplete’ antithrombocyte antibodies with high reproducibility. The two‐stage agglutination test gave positive results in 11 of 21 cases of ITP while the direct agglutination test was positive in only 3 of these cases. It is simple and easy to perform, as it utilizes very small quantities of thrombocytes and requires no washings of the thrombocytes. The direct variation of this test is discussed.

Positive Coombs Test on Blood Platelets

Positive direct anti‐human‐globulin tests on erythrocytes and thrombocytes in three patients suffering from haemolytic anaemia without thromhocytopenia are reported.

SYNERGISTIC ACTION OF ANTIBODIES: DEMONSTRATION OF CIRCULATING LEUKOCYTE ISOANTIBODIES AFTER SKIN TRANSPLANTATION IN RATS AND RABBITS WITH A SUBAGGLUTINATING DOSE OF HETEROANTIBODIES

Local wild strain rabbits weighing between 1 and 3 kg and albino rats of about 250 gr were used. Full-thickness skin homografts, 2 x 1 cm, were performed in rabbits on the inner surfaces of both ears, by a sutureless t e c h n i q ~ e . ~ In rats, one full-thickness transplant, 3 x 2 cm, was sutured on the back and covered by a gauze pressure bandage for five days in first-set and for three days in second-set grafts. In the rabbits, grafts were inspected daily; in the rats, grafts were inspected daily after the removal of the bandage, and progress of rejection was noted. Blood was collected from graft recipients by cardiac puncture a t the time of rejection and later. The sera were inactivated and stored a t 2OoC until the performance of the test. Anti-rabbitand anti-rat-leukocyte sera were prepared by immunization of hens with washed suspensions of pooled rabbit and rat leukocytes respectively, which were injected intravenously and subcutaneously with complete Freund’s adjuvant. The sera were absorbed with washed pooled erythrocytes, free of leukocytes a t room temperature for 30 minutes. A possible weak antiglobulin activity was neutralized by the addition of either normal rabbit or rat serum. Titrations of the sera with rat and rabbit leukocytes, respectively, were performed, and dilutions giving a very weak positive reaction (few leukocyte clumps of 2-4 cells) were used. The dilution medium consisted of physiological salt solution containing 0.05 per cent Nan Sequestrene and 0.05 per cent Triton W.R. 1339.4 Leukocytes were separated from the skin-graft donors’ blood by differential sedimentation, as previously described. A suspension of about 30,00060,000 cells per cmm was prepared. 4