Some aspects of the immune response of koalas (Phascolarctos cinereus) and in vitro neutralization of chlamydia psittaci (koala strains)

Abstract

Western-blot analysis was used to study the reaction of koala antisera, two specific polyclonal antibodies and one monoclonal antibody, with chlamydial antigens in koalas infected with Chlamydia psittaci. The koala sera recognized four C. psittaci surface antigens, corresponding to the major outer membrane protein (39.5 kDa), 31 kDa protein, 18 kDa protein and lipopolysaccharide. The S25-23 LPS specific monoclonal antibody inhibited chlamydial infection (55-67%) with both koala strains (type I and type II). Both koala antiserum and rabbit polyclonal antibodies against either type of chlamydia significantly reduced the number of infected cells resulting from type II infections at a dilution of 1 in 20. Rabbit antiserum against type II was effective in neutralizing infection by type II elementary bodies, but was less effective against type I infection. In addition, no koala antiserum was effective in neutralizing type I infection.

Vaccination of Koalas with a Recombinant Chlamydia pecorum Major Outer Membrane Protein Induces Antibodies of Different Specificity Compared to Those Following a Natural Live Infection

“…Early studies by Girjes et al [23] reported in vitro neutralisation with sera from naturally infected koalas. However, in their study, less than 50% of the sera showed in vitro neutralisation activity and this varied between koalas.…”

From the inside out – processing of the Chlamydial autotransporter PmpD and its role in bacterial adhesion and activation of human host cells

“…Antiserum against peptides representing variable domains of MOMP failed to neutralize infection and a monoclonal antibody against C. pneumoniae LPS was effective only for the strain it was raised against (Peterson et al ., 1996; 1998; Wolf et al ., 2001). Furthermore, immunoreactive surface exposed structures like a glycolipid exoantigen (GLXA, C. psittaci and C. trachomatis ), a 76 kDa and a 54 kDa protein ( C. pneumoniae ) as well as two unknown antigens ( C. pneumoniae ) served as targets for protective antibodies (Girjes et al ., 1993; Gran et al ., 1993; Perez et al ., 1994; Puolakkainen et al ., 1995; An et al ., 1997; Wiedmann‐Al‐Ahmad et al ., 1997). However, we could not differentiate between an inhibition of binding and uptake/invasion and a negative effect of bound antibodies on the course of the chlamydial development after entry into the eukaryotic cell.…”

Association of Uterine and Salpingeal Fibrosis with Chlamydial Hsp60 and Hsp10 Antigen-Specific Antibodies inChlamydia-Infected Koalas

“…Despite these differences in gross anatomy, chlamydial lesions of koalas are similar grossly and histologically to those caused by Chlamydia trachomatis in humans (17). Girjes et al (13) described koala IgG responses to chlamydial lipopolysaccharide (LPS) and 39-kDa (major outer membrane protein), 31-kDa and 18-kDa chlamydial antigens but did not detect serological response to antigens of 10 kDa or 60 kDa by Western blotting. The present cross-sectional study aimed to determine whether koalas recognize the chlamydial antigens c-hsp60 and c-hsp10; whether a relationship exists between disease status and IgG, IgA, and IgE titers against these antigens; and whether, if such a relationship exists, it is applicable to epidemiological surveys of wild koalas.…”