Genetic variation in the recognition of Porphyromonas gingivalis antigens in mice

T-cell cytokine profiles, anti Porphyromonas gingivalis antibodies and West ern blot analysis of antibody responses were examined in BALB/c, CBA/CaH, C 57BL6 and DBA/2J mice immunized intraperitoneally with different doses of P . gingivalis outer membrane antigens, Splenic CD4 and CD8 cells were examin ed for intracytoplasmic interleukin (IL)-4, interferon (IFN)-gamma and IL-L D by FAGS analysis and levels of anti-P. gingivalis antibodies in the serum samples determined by enzyme-linked immunosorbent assay. Western blot anal ysis was performed on the sera from mice immunized with 100 mug of P. gingi valis antigens. The four strains of mice demonstrated varying degrees of T- cell immunity although the T-cell cytokine profiles exhibited by each strai n were not affected by different immunizing doses. While BALB/c and DBA/2J mice exhibited responses that peaked at immunizing doses of 100-200 mug of P. gingivalis antigens, CBA/CaH and C57BL6 demonstrated weak T-cell respons iveness compared with control mice. Like the T-cell responses, serum antibo dy levels were not dose dependent. DBA/23 exhibited the lowest levels of an ti-P. gingivalis antibodies followed by BALB/c with CBA/CaH and C57BL6 mice demonstrating the highest levels. Western blot analysis showed that there were differences in reactivity between the strains to a group of 13 antigen s ranging in molecular weight from 15 to 43 kDa. Antibody responses to a nu mber of these bands in BALB/c mice were of low density, whereas CBA/CaH and C57BL6 mice demonstrated high-density bands and DBA/2J mice showed medium to high responses. In conclusion, different immunizing doses of P. gingival is outer membrane antigens had little effect on the T-cell cytokine respons es and serum anti-P. gingivalis antibody levels. Western blot analysis, how ever, indicated that the four strains of mice exhibited different reactivit y to some lower-molecular-weight antigens. Future studies are required to d etermine the significance of these differences, which may affect the outcom e of P. gingivalis infection.