FIG. 3.

Time course of DT-specific IgG production in huPBL-SCID mice after treatment with rhPRL. huPBL-SCID mice were created and immunized as described in Materials and Methods. Ten micrograms of rhPRL or HBSS was injected i.p. every other day for a total of 20 days. On days 14, 21, and 28 after huPBL transfer, sera were analyzed using a DT-specific ELISA as described in Materials and Methods. The experiment shown had four or five mice per group. The results are expressed in optical density units, as assessed on a spectrophotometer at 450 nm from a 1:100 dilution of each sample. rhPRL significantly (P < 0.05 for day 21; P < 0.01 for day 28) promoted DT-specific IgG production after rechallenge with DT immunization compared with that on day 14.