Related Experiment Videos
Immunoglobulin gene hyperconversion ongoing in chicken splenic germinal centers
H Arakawa1, S Furusawa, S Ekino
1Department of Biophysics, Faculty of Science, Kyoto University, Japan.
The EMBO Journal
|May 15, 1996
Summary
Chicken B-cells diversify after leaving the bursa. Splenic germinal centers facilitate this by using gene conversion and point mutations to create new antibody variants.
Area of Science:
- Immunology
- Molecular Biology
- Avian Genetics
Background:
- Peripheral lymphocytes in chickens were thought to proliferate from a pre-existing repertoire generated in the bursa.
- The mechanisms driving B-cell diversification post-bursal development were not fully understood.
Purpose of the Study:
- To investigate the proliferation and diversification mechanisms of chicken peripheral B-cells.
- To identify the processes responsible for generating antibody diversity in splenic germinal centers.
Main Methods:
- Amplification of rearranged immunoglobulin variable (V) region genes from germinal centers induced by immunization.
- Sequence analysis of amplified V region genes.
- Identification of somatic hypermutations and gene conversion events.
Main Results:
- Most amplified V region genes originated from distinct B-cell clones expanding locally.
- High rates of somatic antibody mutations were observed, including base changes and sequence transfer from V region pseudogenes.
- Evidence of templated gene conversion and untemplated point mutations in splenic germinal centers.
Conclusions:
- Chicken B-cells undergo significant diversification in splenic germinal centers after leaving the bursa.
- Both templated gene conversion and untemplated point mutations contribute to antibody diversification in avian splenic germinal centers.
- This study challenges previous notions of B-cell repertoire generation and highlights ongoing diversification processes.