A family of strain-variant surface lipoproteins of Mycoplasma fermentans
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K S Wise1, M F Kim, P M Theiss
1Department of Molecular Microbiology & Immunology, School of Medicine, University of Missouri-Columbia 65212.
Abstract:
The wall-less procaryote Mycoplasma fermentans is currently being examined as an agent potentially associated with human disease, including infectious processes affecting immunocompromised individuals. To delineate and understand the interactions of M. fermentans with its host, specific membrane surface components were characterized as markers for detecting the organism and for assessing heterogeneity in antigenic surface architecture within this mycoplasma species. Detergent phase fractionation of metabolically labeled organisms of type strain PG18 identified a family of prominent integral membrane proteins; several of these labeled with 35S-cysteine and 3H-palmitate, which are characteristics of procaryotic lipoproteins. Specific monoclonal and polyclonal antibodies raised to strain PG18 components further distinguished seven of these membrane proteins, which were localized on the organism's surface by monitoring their selective susceptibility during trypsin treatment of intact cells. With these antibodies, Western immunoblot profiles of surface membrane antigens expressed on strain PG18 were compared with those expressed on the recently identified Incognitus strain of M. fermentans, as well as with several other human and animal mycoplasma species. While the antibodies were specific for M. fermentans, marked differences were observed between the strains in the size of one surface lipoprotein and in the apparent levels of several antigens expressed in the cultured populations analyzed. Some monoclonal antibodies to strain PG18 and a previously described monoclonal antibody to strain Incognitus showed apparent selectivity for the strain used for immunization. Monoclonal antibodies developed here recognize stable epitopes defining a family of surface lipoproteins and provide critical tools to determine the basis of surface variation in this mycoplasma species and to assess the location and antigenic phenotypes of organisms in the human host.
Insights
Mycoplasma fermentans, a wall-less bacterium, has surface lipoproteins that vary between strains. These variations are key to understanding its interaction with hosts and developing diagnostic tools for Mycoplasma infections.
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Background:
- Mycoplasma fermentans is a wall-less bacterium implicated in human diseases, particularly in immunocompromised individuals.
- Understanding M. fermentans host interactions requires characterizing its surface components for detection and assessing antigenic heterogeneity.
Purpose of the Study:
- To identify and characterize M. fermentans surface membrane proteins as potential diagnostic markers.
- To investigate antigenic variations within M. fermentans strains and related species.
Main Methods:
- Metabolic labeling (35S-cysteine, 3H-palmitate) and detergent phase fractionation of M. fermentans PG18.
- Generation of monoclonal and polyclonal antibodies against strain PG18 surface components.
- Western immunoblotting to compare antigen profiles between M. fermentans strains (PG18, Incognitus) and other mycoplasma species.
Main Results:
- Identification of a family of integral membrane proteins, several characterized as procaryotic lipoproteins.
- Localization of seven distinct surface membrane proteins using antibody-based trypsin susceptibility assays.
- Significant antigenic differences observed between M. fermentans strains, including variations in lipoprotein size and antigen expression levels.
Conclusions:
- Developed monoclonal antibodies recognize stable epitopes on M. fermentans surface lipoproteins.
- These antibodies are crucial tools for studying the basis of surface variation in M. fermentans.
- The findings facilitate assessment of organism location and antigenic phenotypes in human infections.