Modulation of human lymphocyte transformation by bacterial products and leukocyte lysates.

Blast transformation of human peripheral blood lymphocytes by PHA is shown to be modulated by lipoteichoic acid (LTA) of Streptococcus mutans, by a cell-sensitizing factor of Actinomyces viscosus, as well as by a frozen and thawed extract of human leukocytes (LE). While small amounts of LE (5-50 micrograms/10(6) cells) significantly enhanced PHA-induced transformation, higher amounts showed a lesser effect on the blastogenic response. Both LTA and the A. viscosus extract did not cause any lymphocyte blastogenic effect when used alone. On the other hand LTA had an inhibitory effect and the A. viscosus extract had an enhancing effect when lymphocytes were pretreated by these agents and then exposed to PHA.