Susceptibility to reinfection after a primary chlamydial genital infection

Abstract

Female guinea pigs which had been infected genitafly with the agent of guinea pig inclusion conjunctivitis were chaflenged at various times after infection with fresh inocula to determine the duration of immunity resulting from the primary infection. At 30 days after infection, most guinea pigs were resistant to reinfection, as indicated by the inability to isolate chlamydiae from cervical swabs. However, at 77, 155, and 294 days, all animals became reinfected, although the course of the infection was abbreviated and of lower intensity. When various immune parameters were examined, a decrease in antibodies in both serum (immunoglobulin G ([IgG]) and genital secretions (IgA, IgG) was observed after 30 days. A decrease in antibodies to the major outer membrane protein and an 84K component was noted in serum. In genital secretions, IgA antibodies to all major chlamydial components declined markedly after 30 days. Cell-mediated immunity as measured by proliferation of peripheral blood lymphocytes to guinea pig inclusion conjunctivitis antigen also was at a peak response 30 days after infection and decreased thereafter. Thus, loss of complete immunity could not be associated with a particular immune parameter. When genital secretions were examined 14 days after the challenge infection, IgA antibody levels to the lipopolysaccharide and 61K protein components had increased in intensity, whereas other antibodies were relatively low. In addition, complete immunity to a third infection was not increased in duration when animals had recovered from two previous genital infections.

The immune response against Chlamydia suis genital tract infection partially protects against re-infection

“…This presumption is in accordance with human epidemiologic studies suggesting that prior genital infection with Chlamydia trachomatis, which is phylogenetically highly related to C. suis, confers some short term protection against re-infection [35,36]. Moreover, in all evaluated animal models of genital chlamydial infection, including the mouse [37], guinea pig [38] and macaque [39], it has been demonstrated that at least partial immunity to re-infection develops. Nevertheless, vaginal inoculation with C. suis resulted in an ascending infection in both groups.…”

Protein antigens of Chlamydia psittaci present in infected cells but not detected in the infectious elementary body

“…To our knowledge, this is the first description of chlamydial antigens not detected in purified EBs. In the guinea pig system, several authors have identified GPIC antigens which are recognized in the context of infection, but the antigens uniformly used in immunoblots were lysates of purified GPIC EBs (3,22,29). Many approaches have been used to examine the antigenicity of MOMP, LPS, and the 60-kDa proteins (2, 30, 32; reviewed in reference 18), and additional EB antigens have been identified in surveys of the antibody response in infected humans and infected or immunized animals.…”

Protective role of serum antibody in immunity to chlamydial genital infection

“…Hartley strain female guinea pigs, weighing 450 to 500 g, were obtained from Sasco Laboratories, Omaha, Nebr., and were housed individually in an environmentally controlled room with a 12-h light-dark cycle. Guinea pigs were infected in the genital tract with GPIC which had been grown in HeLa cells (15). Each animal received approximately 1.4 x 107 inclusion-forming units contained in 0.05 ml of sucrosephosphate-glutamate buffer (pH 7.4) (18).…”

“…Each animal received approximately 1.4 x 107 inclusion-forming units contained in 0.05 ml of sucrosephosphate-glutamate buffer (pH 7.4) (18). The course of the infection was monitored by determining the percentage of inclusion-bearing cells on a Giemsa-stained smear of a scraping from the vaginal vault (15). Antibody titers in serum and genital secretions were determined by an enzyme-linked immunosorbent assay, using GPIC elementary bodies grown in HeLa cells as the antigen (4).…”