Enhancement of LAK-like activity and cytokine induction in regional lymph nodes and spleen cells of mice after intralymphnodal injection of OK-432, a killed streptococcal preparation

A single dose of inactivated streptococci (OK-432) was injected into the popliteal lymph nodes of male CDF1, mice and its effects on popliteal, inguinal, and para-aortic lymph node cells and spleen cells were investigated and compared with the effects of subcutaneous injections of the same dosage of OK-432. Regional lymph node cells and spleen cells obtained from intralymphnodally injected mice lysed not only natural killer (NK)-sensitive YAC-1 cells, but also NK-resistant P-815 and meth-A cells. Lysis of target cells was inhibited when effector cells were treated with anti-Thy-1.2 or anti-Lyt-2.2 monoclonal antibody and complement, but no inhibition was apparent after treatment with anti-asialo-GM1 or anti-Lyt-1.2 antibody and complement. These results suggest that the effector cells are lymphocyte-activated killer (LAK) cells. An enhanced capacity of lymph node cells to produce cytokines, tumor necrosis factor and Interleukin 1 upon restimulation with lipopolysaccharide was found only in intralymphnodally injected mice. Thus, the induction of LAK-like cells and cytokine production in regional lymph nodes and spleen cells by the intralymphnodal administration of OK-432 should be effective for the inhibition or treatment of lymph node metastases.