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Search for cross-reactivity between HLA B27 and Klebsiella pneumoniae
Abstract:
HLA B27 is associated with a number of forms of arthritis, including ankylosing spondylitis. It has been suggested that the disease is caused by Klebsiella pneumoniae and that the bacterium evokes an odd immune response because it cross-reacts with HLA B27. This proposed cross-reactivity was investigated in a number of ways. The results consistently failed to confirm evidence from cross reaction, even in antisera with activity against both HLA B27-positive lymphocytes and klebsiella. It is suggested that the anomalous anti-klebsiella response of rabbits immunised with pools of HLA B27-positive leucocytes may be caused by antigenic bacterial fragments on the cells of infected individuals.
Insights
Human Leukocyte Antigen B27 (HLA B27) is linked to ankylosing spondylitis. This study found no evidence that the bacterium Klebsiella pneumoniae cross-reacts with HLA B27, suggesting fragments may cause immune responses.
Area of Science:
- Immunogenetics
- Rheumatology
- Microbiology
Background:
- The Human Leukocyte Antigen B27 (HLA B27) gene is strongly associated with inflammatory arthropathies, particularly ankylosing spondylitis.
- A hypothesis suggests that the bacterium Klebsiella pneumoniae may trigger these conditions through molecular mimicry, where bacterial antigens cross-react with HLA B27.
- This proposed cross-reactivity has been investigated as a potential mechanism for the development of HLA B27-associated arthritis.
Purpose of the Study:
- To investigate the proposed cross-reactivity between Klebsiella pneumoniae and Human Leukocyte Antigen B27 (HLA B27).
- To determine if molecular mimicry between the bacterium and the human leukocyte antigen plays a role in HLA B27-associated inflammatory diseases.
Main Methods:
- Serological assays were performed using antisera with known reactivity against both HLA B27-positive lymphocytes and Klebsiella pneumoniae.
- Immunological cross-reactivity was assessed through various experimental approaches to detect shared epitopes.
- Animal models were utilized, including rabbits immunized with HLA B27-positive leukocytes to observe immune responses.
Main Results:
- The study consistently failed to confirm cross-reactivity between Klebsiella pneumoniae and HLA B27 across multiple experimental methods.
- Antisera designed to detect activity against both HLA B27 and Klebsiella did not provide evidence of molecular mimicry.
- Rabbits immunized with HLA B27-positive leukocytes exhibited an anomalous immune response against Klebsiella, but this was not attributed to direct cross-reactivity.
Conclusions:
- The findings do not support the hypothesis that Klebsiella pneumoniae directly cross-reacts with HLA B27 in the context of ankylosing spondylitis.
- The observed immune responses in immunized rabbits are suggested to be due to the presence of antigenic bacterial fragments on infected host cells.
- Further research is needed to elucidate the precise mechanisms linking bacterial infections and HLA B27-associated inflammatory conditions.