Kinetics of serum, tear, and corneal antibody responses in resistant and susceptible mice intracorneally infected with Pseudomonas aeruginosa

Abstract

The studies described here are aimed at determining the kinetics of antibody responses specific to Pseudomonas aeruginosa ATCC 19660 in sera, tears, and corneas of naturally resistant DBA/2 mice and susceptible C57BL/6 mice after intracorneal infection. Immunoglobulin (IgG) and IgM responses in sera were significantly greater in DBA/2 mice for the first 2 weeks postinfection. Little or no IgA was detected in the sera of mice from either strain. IgG was the predominant immunoglobulin class present in the corneas of the infected eyes from both mouse strains. However, differences in both the magnitude and the kinetics of the corneal IgG responses were noted between mouse strains. The kinetics of the corneal IgG responses were more similar to those of the serum IgG response than to those of the tear IgG response. Tear antibody responses in DBA/2 mice differed from those of C57BL/6 mice in two ways. First, there was a sharp increase in tear IgG levels 2 weeks after infection in DBA/2 mice that was not present in C57BL/6 mice. Second, IgA levels present in tears from the infected eyes of C57BL/6 mice dropped to nearly preinfection levels after the first week, whereas in DBA/2 mice, IgA levels remained elevated in the infected eyes after the first week. Determination of P. aeruginosa-specific antibody responses in the uninfected, contralateral control eyes revealed that IgA was detectable in the tears but not in the corneas of DBA/2 mice. Very little IgA was detected in the tears of the uninfected eyes of C57BL/6 mice. IgG was the only immunoglobulin class present in the uninfected corneas in both mouse strains tested. These results suggest that ocular IgA was made locally, whereas most ocular IgG may have originated from the serum, with some possible local synthesis. These immunological results indicate that DBA/2 and C57BL/6 mice respond differently to corneal challenge with P. aeruginosa.