SUMMARYTbe route of immunization was observed to play a significant role in deciding the outcome of immunization with killed mycobacterial vaccines. Wbereas the slow growers were immunogenic by both intraperitoneal and intradermal routes, the rapid growers were immunogenic only by intradcrmal route. The non-rcsponder state of miee to Mycobacterium vaccae by i.p. route of immunization eould be corrected by prior treatment with poly I: poly C, an interferon inducer, or indomethacin, a prostaglandin inhibitor. Antigen-presenting efficiency of peritoneal and spleen cells were compared employing M. vaccae and M. tuberculosis H37Rv primed T cells and corresponding sonicates as antigens in an in vitro lymphoeyte transformation test. Irradiated spleen eells presented both the antigens efficiently. However, with peritoneal cells as antigen-presenting cells, proliferative response against only M. tubercutosis was observed; proliferation of M. vaccae primed T cells was very poor. Peritoneal cells of poly I:poly C treated mice showed distinct improvement in their efficiency of presentation; even para formaldehyde-fixed peritoneal cells gave an efficient stimulation with M. vaccae. The percentage of la-positive fraction in peritoneal cells was very low (5-95%) in comparison with spleen cells (38-37'^n). Poly I: poly C treatment resulted in increase in tbe la-positive cell fraction ofthe peritonea! cells to 24-5"';i.

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The saw-scaled viper (Echis carinatus) is one of the principal causes of snake bites in India. For the Haffkine Institute, these snakes are procured for their venom every year from the Deogad area. A study of prevalence and distribution of these snakes was, therefore, undertaken to find out the areas where their prevalence is at the highest. Echis carinatus were invariably found under stones in open fields. Maximum numbers of snakes were collected during the rainy months. A study of output of venom by snakes procured during different months revealed that snakes collected during August produced less venom in comparison to snakes procured in October.

The histocompatibility antigens are thought to be the principal genetic factor in disease susceptibility and expression (Bach & van Rood, 1976). This antigen system has been studied in various autoimmune disorders and high incidence of certain HLA antigens has been observed in many diseases. Recently, Goebal et al (1977), while screening 20 patients with ITP, found a high incidence of HLA-B8 and HLA-B12 either alone (70% and 45% respectively) or in combination (40%) as compared to controls which included patients with drug-induced thrombocytopenic purpura and healthy volunteers.We subjected our 20 patients with ITP to HLA phenotype studies. The criteria for the diagnosis of ITP included: (a) a platelet count of less than 100 x 109/l; (b) megakaryocytic hyperplasia with poor platelet production in the bone marrow; and (c) exclusion of any systemic disease, other haematological disorder and antecedent history of intake of drugs o r toxins related to this disorder. Antiplatelet antibodies were present in 12 out of 20 cases (60%) as tested by the platelet factor 3 release test (Karpatkin & Siskind, 1969).HLA profiles were assayed by the two-stage microlymphocytoxity test (Mittal et al, 1968). Well-defined antisera against 23 specificities were used to identify the antigens. Three or four antisera were used against each specificity. Sixty controls included healthy members of our staff and unrelated voluntary donors for patients waiting for renal transplantation. All the patients and controls were from North India and represented the same ethnic group of population. All but three of the patients had not received steroid therapy for more than 6 weeks at the time of HLA phenotyping. One of these patients had been on 20-30 mg of prednisolone per day for 2 months when his HLA typing was carried out. The two other patients had been taking 5-10 mg of prednisolone intermittently for about 2 years when their HLA phenotyping was carried out; one of them had undergone therapeutic splenectomy.HLA-B8 was present in 15% (three patients) as compared to 13.3% in the control. HLA-B12 was observed in 10% (two patients) as compared to 20% in the control population. Combination of HLA-B8 and B12 was not observed in any patient. Statistical analysis using Yates chi-square test did not show any significant association of HLA-B8, B12 or any other HLA antigen with ITP as compared to controls. The present data therefore do not reveal any association between the HLA antigens and ITP in this ethnic group.

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