Examinations of the immunogenicity of the experimental bivalent subunit vaccines against herpes simplex virus type 1 and 2

The objective of our study was to check the immunogenicity of experimental bivalent subunit vaccines against Herpes simplex viruses (HSV1 and HSV2). T he subunit vaccines were prepared from glycoprotein antigens isolated from the external envelopes of HSV1 and HSV2. In the first vaccine the glycoprot eins subunits were adsorbed on the adjuvant Al(OH)3. The secortd subunit va ccine was prepared from glycoprotein antigens with the adjuvant MPs-19 (a w ater soluble oligosaccharide) dissolved in phosphate buffered saline (PBS). The final concentration of Al(OH)3 in the first vaccine was 5mg/ml, while the final concentration of MPS-(19) in the second vaccine was 2 mg/ml. Thes e vaccines contained 0.13 mg total protein for the HSV1 subunits and 0.16 m g for the HSV2 subunits ml. One group of 10 female Swiss albino mice (20 gr body weight) were each immunized s.c. with 0.5 ml of the HSV1/HSV2 subunit vaccine, containing the adjuvant Al(OH)3. The second group of 10 mice was immunized with the same quantity of the HSV1/HSV2 subunit vaccine with adju vant MPS-19. A group II healthy nonimmunized mice served as the control in the assay. The specific humoral immune response of the vaccinated mice was measured by a standard method of indirect immunofluorescence. The specific cellular immune response of the vaccinated animals was tested by measuring the lymphocyte proliferation response to HSV1 and HSV2 antigens with tritiu m methyl thymidine *128.5 Bq/mmol), in vitro. The titres of the specific Ig G and IgM class antibodies, in the sera of both groups of immunized mice on day 10 after vaccination were: a) with adjuvant Al(OH)3: from 1.8 to 1:128 IgG; and 1:32 to 1:128 IgM for HSV1; from 1:32 to 1:128 IgG and IgM antibo dies, for HSV2; b) with adjuvant MPS-(19); from 1.16 to 1:128 IgG and 1:64 to 1:128 IgM for HSV1; from 1:16 to 1:32 IgG and 1:64 to 1:128 IgM for HSV2 . The mean values for radioactivity in the medium after spontaneous prolife ration of lymphocytes were 799 cpm for the first and 798 cpm for the second experimental group. The mean radioactivity of lymphocytes from the first g roup of mice stimulated with HSV1 and HSV2 antigens in, 10 days after immun ization, was 1470 cpm (for HSV1) and 1845 cpm (for HSV2). The mean values o f radioactivity in the proliferation test for HSV1 and HSV2 antigens in the second (for HSV1) and 2416 cpm (for HSV2). Thus, the low subunit antigen c oncentrations in both vaccines, induced satisfacton/humoral and cellular im mune responses to HSV1 and HSV2 in the organisms of immunized mice.