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Characterization of the metabolism inhibition antigen of Mycoplasma arthritidis
Abstract:
The Mycoplasma arthritidis antigen(s) responsible for eliciting metabolism-inhibiting antibodies in rabbits has been partially characterized. Metabolism-inhibiting activity was absorbed from rabbit antisera by intact M. arthritidis cells and membranes but much less so by the soluble cytoplasmic fraction, indicating that the antigen is located on the outer membrane surface. It was stable to periodate and lipid extraction but labile to heat and proteolytic enzymes, indicating that it is protein in nature. Finally, it is most likely a tightly bound integral rather than a peripheral membrane protein, since it was not extracted by low-ionic-strength solutions or by the nonionic detergents Triton X-100, Nonidet P-40, and Tween 20. It was solubilized by both the anionic agent sodium deoxycholate and the zwitterionic detergent Zwittergent. Two two monoclonal antibodies with metabolism-inhibiting activity were produced. One recognized a 45,000-dalton surface protein; however, the other recognized an antigen which is probably of cytoplasmic origin, indicating that more than one cell component may be involved in the metabolism-inhibiting antibody response.
Insights
Researchers identified a protein on the outer membrane of Mycoplasma arthritidis as a key antigen. This antigen triggers metabolism-inhibiting antibodies, crucial for understanding immune responses to this bacterium.
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Background:
- Mycoplasma arthritidis is a bacterium known to elicit immune responses.
- Understanding the antigens responsible for specific antibody production is vital for immunological studies.
Purpose of the Study:
- To partially characterize the Mycoplasma arthritidis antigen(s) that induce metabolism-inhibiting antibodies in rabbits.
- To determine the location and nature of the antigen(s).
Main Methods:
- Absorption of metabolism-inhibiting activity from rabbit antisera using different fractions of M. arthritidis (intact cells, membranes, cytoplasmic fraction).
- Stability testing of the antigen against periodate, lipid extraction, heat, and proteolytic enzymes.
- Solubilization assays using various detergents (Triton X-100, Nonidet P-40, Tween 20, sodium deoxycholate, Zwittergent).
- Production and characterization of monoclonal antibodies against the antigen.
Main Results:
- The antigen is located on the outer membrane surface, as indicated by absorption studies.
- The antigen is proteinaceous, evidenced by its stability to periodate/lipid extraction and lability to heat/proteolytic enzymes.
- It behaves as a tightly bound integral membrane protein, requiring anionic or zwitterionic detergents for solubilization.
- One monoclonal antibody recognized a 45,000-dalton surface protein, while another recognized a potential cytoplasmic antigen.
Conclusions:
- A protein antigen on the outer membrane of Mycoplasma arthritidis is a primary target for metabolism-inhibiting antibodies.
- The characterization suggests it is an integral membrane protein.
- The existence of a second, possibly cytoplasmic, antigen involved in the response indicates complexity in the antibody generation.