Accumulation of chlamydial lipopolysaccharide antigen in the plasma membranes of infected cells

Abstract

The presence of a chlamydia-specified antigen associated with the plasma membrane of infected cell lines was demonstrated by indirect immunofluorescence staining with a monoclonal antibody, designated 47A2, specific for the chlamydial genus-specific lipopolysaccharide (LPS) antigen. Staining of HeLa, L-929, and McCoy cells infected with the L2 or F serovar of Chlamydia trachomatis was observed either without fixation or following aldehyde fixation and brief drying. The 47A2-reactive antigen appeared to be present on the plasma membrane, on bleb-like structures on the host cell surface, and on proximal processes of neighboring uninfected cells. Antibodies to chlamydial protein antigens such as the major outer membrane protein produced no surface staining under similar conditions. Membrane vesicles elaborated from infected cells were enriched for the 47A2-reactive antigen. Superinfection of chlamydia-infected cells with vesicular stomatitis virus, an enveloped virus which buds from the plasma membrane, allowed purification of progeny virions that were enriched with chlamydial LPS. These results are consistent with the presence of chlamydial LPS in the plasma membranes of infected host cells.

Chlamydia trachomatis enters a viable but non-cultivable (persistent) state within herpes simplex virus type 2 (HSV-2) co-infected host cells

“…Chlamydial major outer membrane protein (MOMP) expression is often decreased during persistence while expression of the chlamydial proinflammatory antigen, heat‐shock protein 60 (HSP60‐1), is stable or increased (Cevenini et al ., 1988; Beatty et al ., 1993; 1994c). Persistent chlamydial forms shed MOMP and lipopolysaccharide (LPS) into membrane blebs, which find their way to the host cell surface and are released (Karimi et al ., 1989; Wyrick et al ., 1994; 1997; 1999). Although C. trachomatis persistence in vivo has been difficult to demonstrate, recent studies suggest that C. trachomatis establishes persistent infections in humans (Patton et al ., 1994; Fortenberry et al ., 1999; Dean et al ., 2000; Gerard et al ., 2001; 2002).…”

Current Methods of Laboratory Diagnosis of Chlamydia Trachomatis Infections

“…The blocking antibody reagent used for Chlamydiazyme has been found in one study to agree well with confirmation by DFA tests with MOMP-specific monoclonal antibody (67), but in another study, 24% of EIA-reactive, blocking test-negative specimens were positive by DFA (244). Since LPS is more soluble than MOMP and significant quantities of LPS are deposited on the surface of infected cells during acute infection (93), the concentration of blocking antibody contained in the commercial reagent may be insufficient to suppress reactivity in some specimens. Regardless of the use of blocking reagent, Chlamydiazyme is reported not to be useful for female urine specimens due to its lack of sensitivity and its high rate of false-positives (39,99).…”

The intracellular life of Chlamydia psittaci: how do the bacteria interact with the host cell?

“…However, in those investigations where LPS was detected, a variety of di¡erent ¢xatives was used. Furthermore, Karimi et al [46] showed the presence of chlamydial LPS in viral envelopes after C. trachomatis-infected cells were superinfected with a virus, demonstrating that the LPS of Chlamydia is indeed incorporated into the host plasma membrane, since the virus acquired its envelope by budding from the plasma membrane. In contrast, no MOMP was detected on virion progeny.…”

“…It could also be an event dependent on the infecting strain. Karimi et al [46] suggested that the LPS destined to appear in the plasma membrane may originate during the morphological transformation of RBs into EBs since during condensation large amounts of outer membrane are probably shed as intracellular vacuoles. This hypothesis was recently con¢rmed by Vanrompay et al [109] who observed this antigen in membranous vesicles within the chlamydiae-containing vacuole, which were apparently pinched o¡ from the outer membrane of reticulate bodies.…”

“…Accumulation of chlamydial LPS into the vacuole membrane a¡ects its £uidity, and this may a¡ect endocytic processes and lysosomeendosome fusion [46]. 9.…”