[Delayed type hypersensitivity responses to recombinant mycobacterial antigen 38,000 in guinea pigs sensitized to...

To evaluate the ability and influencing factors that recombinant 38,000 antigen induces delayed-type hypersensitivity(DTH) reaction in guinea pigs.

In one skin test, physiological saline as negative control and PPD as positive control, guinea pigs were shaved on the back and given intracutaneous injection with 0.1 microgram, 0.2 microgram, 0.4 microgram of recombinant 38,000 antigen. Skin reactions were measured 48 h after antigen injection, each measuring two transverse diameters of the induration. In the other skin test, each guinea pig was intracutaneously injected in four sites, respectively with 5 IU PPD and recombinant 38,000 antigen (0.1 microgram, 0.2 microgram and 0.4 microgram) or 5 IU PPD and biantigen(combination 38,000 with 16,000 antigen, 0.1 microgram, 0.2 microgram and 0.4 microgram). Single antigen and biantigen were tested in three separate experiments. Each experiment needs six sensitized guinea pigs. Skin reactions were measured 24 h, 48 h and 72 h after antigen injection.

DTH responses induced by 0.4 microgram were weaker than 0.1 microgram and 0.2 microgram in 24 h. 0.1 microgram and 0.2 microgram elicited DTH responses similar in strength to that of 5 IU PPD. From 0.1 to 0.4 microgram, similar dose of recombinant 38,000 antigen and combination antigen elicited similar DTH responses. DTH responses induced by recombinant 38,000 antigen had better be measured at 48 h, however that induced by combination antigen at 24 h.

Recombinant 38,000 antigen can induce DTH responses in guinea pigs. Dose of antigen is important factor that affect DTH responses in guinea pigs.