INVITRO DEVELOPMENT OF 3RD-STAGE AND 4TH-STAGE LARVAE OF DIROFILARIA-IMMITIS - COMPARISON OF BASAL CULTURE MEDIA, SERUM LEVELS AND POSSIBLE SERUM SUBSTITUTES
In vitro development and survival of 3rd-stage larvae of D. immitis were compared in 4 different culture media and in the presence of varying concentrations of 4 different medium supplements. Motility and the incidence of 3rd- to 4th-stage medium supplements. Motility and the incidence of 3rd- to 4th-stage molting were used as criteria for evaluating different culture conditions. No significant differences in either motility or molting response were detected between larvae cultured in NCTC-135, F12(K), CMRL 1066 or Dulbecco''s Modified Eagle''s Medium. Fetal calf serum enhanced development and survival of the cultured larvae in dose-dependent fashion. It effects were maximal at a concentration of 20% of the total medium volume. Addition of a commercial medium supplement, NuSerum, also gave a dose-related increase in larval development and viability. The activity of NuSerum in this respect was comparable to that of fetal calf serum. The tripeptide glycylhistidyllysine and bovine serum albumin, fraction V both failed to stimulate development of 3rd-stage D. immitis larvae in vitro.