Suppression of Transferred Lymph Node Cells by Rabbit-Antirabbit Leukocyte Serum

Abstract

Summary It was shown earlier that if rabbits given rabbit lymph node cells incubated in vitro with Shigella antigen were injected with pooled rabbit-anti-rabbit leukocyte serum, the production of anti-Shigella agglutinins in these recipients was reduced in comparison with recipients given the cells alone. In the present study a number of further observations have been made on the production of such antileukocyte sera, and their effects when incubated with lymph node cells prior to the transfer of these cells. When antirabbit leukocyte sera obtained after a single intradermal injection of leukocytes were incubated with rabbit lymph node cells prior to transfer of the cells, reduction of the level of agglutinin titers of these recipients was found. For each such serum pool there was a range of amounts within which the degree of suppression of the transferred lymph node cells was a function of the amount of such serum with which the lymph node cells had been incubated prior to transfer. In the case of sera obtained after a second injection of rabbits with rabbit leukocytes, such a relation could also be observed, the sera being approximately 10 times as effective as sera obtained after a single injection of pooled leukocytes. Sera obtained after intradermal injection of rabbits with rabbit leukocytes were more effective in suppressing the transferred lymph node cells than those obtained by intravenous injection of such leukocytes. Removal of excess antileukocyte serum by centrifugation and washing of the lymph node cells did not affect the degree of suppression of these cells. When the lymph node cells were obtained from donor animals injected with Shigella the suppressive effect of the antileukocyte serum on the transferred cells was clearly observed, even when the cell transfer was performed within a day of the expected time of appearance of antibody in the recipient animals. The injection of rabbit-antirabbit leukocyte serum into recipients after the transfer of antigenincubated lymph node cells caused a decrease in the titer of agglutinins to Shigella. This was demonstrable even when the serum was injected 3 days after cell transfer, or within a day of the time of appearance of the antibody in the recipients' sera.