Complement Enhancement of Neutralizing Antibody to the Structural Proteins of Chlamydia trachomatis

Megran, D W; Stiver, H Grant; Peeling, R.; Maclean, Ian; Brunham, Robert C.

doi:10.1093/infdis/158.3.661

Cited by 15 publications

(10 citation statements)

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“…For example, as discussed above, a correlation exists between neutralization of the intracellular bacterium Chlamydia trachomatis and coating of the infectious elementary bodies with antibody (Peeling and Brunham, 1991). Complement may enhance neutralization of opsonized C. trachomatis (Megran et al, 1988). Passive transfer of an antibody against an outer surface protein of Borrelia burgdorferi, which strongly stained nonpermeabilized B. burgdorferi cells, completely protected mice from challenge (Mbow et al, 1999).…”

Section: Observations With Nonviral Pathogensmentioning

confidence: 96%

The antiviral activity of antibodies in vitro and in vivo

Parren

Burton

2001

Advances in Immunology

236

191

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Section: Observations With Nonviral Pathogensmentioning

confidence: 96%

The antiviral activity of antibodies in vitro and in vivo

Parren

Burton

2001

Advances in Immunology

236

191

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“…Neutralization of chlamydial infectivity probably occurs both before and after entry into the host cell (4, 20) through a variety of mechanisms, some of which are complement dependent.Several studies have shown that chlamydiae can activate the complement cascade in fresh serum in vitro (16) and that complement greatly enhances the neutralization of infectiv-* Corresponding author. ity by antibody (13,17). Although complement is activated by EBs in the absence of antibody, it does not neutralize chlamydiae without specific antibody as it does other "serum-sensitive" gram-negative bacteria (9).…”

mentioning

confidence: 99%

Characterization of kinetics and target proteins for binding of human complement component C3 to the surface-exposed outer membrane of Chlamydia trachomatis serovar L2

Hall

Strugnell

et al. 1993

Infect Immun

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In order to characterize the interaction of human complement with Chlamydia trachomatis, flow cytometry was used to quantitate binding of complement component C3 to elementary bodies of C. trachomatis serovar L2 preincubated in fresh serum in the presence or absence of human polyclonal chlamydial antibody. Isolation of each of the complement activation pathways revealed that C3 was activated most effectively by the alternative pathway. The degree of binding by the classical pathway was proportional to the concentration of antibody, but dual-pathway-mediated binding was not greater than antibody-independent alternative pathway binding. Electrophoresis and immunoblotting of detergent-extracted outer membrane protein-C3b complexes indicated that the chlamydial major outer membrane protein was the primary cell surface moiety binding C3b in both the presence and absence of specific antibody. Hydroxylamine cleavage of outer membrane protein-C3b complexes provided evidence that the majority of C3b is bound to the major outer membrane protein by hydroxyl ester bonds. This result was also unchanged by the presence of specific antibody. An unexpected finding was the apparent binding of anti-C3 antibody to a 40-kDa protein of the chlamydial outer membrane complex, perhaps indicating C3 mimicry on the part of the chlamydial major outer membrane protein.Chlamydia trachomatis is an obligate intracellular bacterium causing conjunctivitis, urethritis, and pelvic inflammatory disease. It is characterized by a dimorphic life cycle, consisting of the intracellular, metabolically active reticulate body and, after lysis of the host cell, the inert, infectious elementary body (EB), which is released into the extracellular environment (18). The interaction of EBs with host resistance factors in the extracellular milieu is an important area of chlamydial research in which there remain many unanswered questions.The cell surface of C. trachomatis EBs has been studied extensively with monoclonal antibodies (MAb) to map and catalog the antigenic profiles of the outer membrane proteins (OMPs). Studies of these membrane antigens have revealed that the major OMP (MOMP) binds specific antibody and plays an important role both structurally and immunologically (20, 21). It is surface exposed at its four immunochemically variable domains (1), which bear the species and subspecies determinants for C. trachomatis serovars. Su and Caldwell (25) showed that Fab fragments of an MAb directed against the MOMP exerted a neutralizing effect by preventing chlamydial attachment to the host cell, indicating a possible role for the MOMP as an adhesin molecule in infectivity. Neutralization of chlamydial infectivity probably occurs both before and after entry into the host cell (4, 20) through a variety of mechanisms, some of which are complement dependent.Several studies have shown that chlamydiae can activate the complement cascade in fresh serum in vitro (16) and that complement greatly enhances the neutralization of infectiv-* Corresponding author. ity by a...

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“…Lower infectivity and lower neutralization rates were obtained in the absence of complement. Previous studies have also shown that complement enhances antibody-mediated neutralization while it had no effect by itself on chlamydial inactivation [3,11,12].…”

Section: Infectivity Of Mccoy Anda-431 Cells By C Trachomatis Serovamentioning

confidence: 97%

Monoclonal antibody neutralization of unmanipulated Chlamydia trachomatis serovar A infection of human epithelioid cells (A-431)

Barsoum

Goodman

Hardin

et al. 1989

Med Microbiol Immunol

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A human epithelioid cell line (A-431) was tested in parallel with McCoy fibroblast cells for the growth of trachoma-related serovar A Chlamydia trachomatis without centrifugation or cycloheximide addition. A-431 cells were 4-7 times more susceptible to infection with serovar A than McCoy cells in such unmanipulated cultures. Murine monoclonal antibodies (MAbs) developed against serovar A were then evaluated for their ability to inhibit unmanipulated serovar A infectivity of A-431 cells. Two of seven MAbs tested neutralized infectivity by more than 50%. An IgG2a MAb (2C8) that is specific for serovar A, and another IgG2a MAb (4E3) that reacts equally with serovars A and L2 neutralized infectivity of serovar A by 72.2 +/- 3.7% and 56.0 +/- 5.8% (mean +/- SEM of 7 experiments) respectively. Mouse immune serum (MIS) raised against serovar A elementary bodies (EB) neutralized infectivity of serovar A by 76.0 +/- 4.9% (mean +/- SEM of 7 experiments). Immunoblot detection of serovar A EB polypeptides separated by SDS-PAGE indicated that 2C8 reacted with a 16 kD and 4E3 reacted with a 12 kD polypeptide while MIS reacted with several polypeptides including the major outer membrane protein (MOMP). These studies show that the human epithelioid cell line A-431 is a more susceptible host than McCoy cells in unmanipulated cultures, and that 2 MAbs neutralize serovar A infectivity of A-431 cells. Identification of antigenic moieties of importance in unmanipulated chlamydial infections may help in the development of potential vaccines against trachoma.

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Complement Enhancement of Neutralizing Antibody to the Structural Proteins of Chlamydia trachomatis

Cited by 15 publications

References 0 publications

The antiviral activity of antibodies in vitro and in vivo

The antiviral activity of antibodies in vitro and in vivo

Characterization of kinetics and target proteins for binding of human complement component C3 to the surface-exposed outer membrane of Chlamydia trachomatis serovar L2

Monoclonal antibody neutralization of unmanipulated Chlamydia trachomatis serovar A infection of human epithelioid cells (A-431)

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