Immunomodulatory properties of a strain of Mycobacterium chelonae—II. Qualitative and quantitative stimulation of mouse splenocytes by Mycobacterium chelonae

Abstract

Intraperitoneal [i.p.] and subcutaneous [s.c.] administration to BALB/C mice with a single dose of 5 mg/kg body weight (wet weight) of live Mycobacterium chelonae (Mch) augmented splenocyte blastogenesis. Similar increases in splenocyte blastogenesis manifested during a single oral administration to mice with 100 mg/kg body weight (wet weight) of this Mycobacterium. When splenocytes issued from these mice are activated by mitogens, a highly significant enhancement of lymphoblastic transformation was observed. On the other hand, multiple oral administrations with 50 mg/kg body weight (wet weight) to Mch/dose did not manifest statistically significant differences in splenocyte blastogenesis as compared to controls. Meanwhile, a highly increased transformation of splenocytes, issued from such mice, is observed in response to lectins and to the mitogenic effect of this microorganism. Splenocyte counts have shown 44.5, 37.6, and 23.2% increases in response to i.p., s.c. and multiple oral administration of this bacterium, respectively, as compared to solvent controls. Repeated s.c. administration of this mycobacterium manifested short lived and weak syndromes of anaphylactic shock during and immediately after the second inoculation of Mch. This phenomenon is not observed during repeated intraperitoneal and oral administrations. In conclusion, parenteral (i.p. and s.c.) and oral administration of Mch stimulates the immune system of mice. This effect is characterised by increased in vivo cell multiplication and by enhanced ex vivo DNA synthesis of murine splenocytes. The need of further studies is eminent to elucidate classes of immunocompetent cells involved in this phenomenon.