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Updated: Aug 9, 2026
The Lambda Select cII Mutation Detection System
Published on: April 26, 2018
Analysis of somatic mutation activity in multiple V kappa genes involved in the response to 2-phenyl-5-oxazolone
E Källberg1, D Gray, T Leanderson
1Immunology Unit, Lund University, Sweden.
Abstract:
We have studied somatic mutation activity early in a response to 2-phenyl-5-oxazolone coupled to ovalbumin (phOx-OVA). Although the V kappa Ox1 gene rearranged to J kappa 5 is known to predominate in this response, other closely related V kappa genes are involved. We compared the introduction of point mutations into V kappa Ox1 genes and into a set of related V kappa genes rearranged to the same J kappa segment at two time points after primary immunization. The result showed that quantitation of mutations in a single rearrangement substrate leads to an underestimation of the total mutational activity. There is pronounced somatic mutation activity early within genes that may be absent later in the response. We also show that multiple somatic mutations can be detected in B cells from draining lymph nodes after foot-pad injection with phOx-OVA already at day 7 after immunization. The data suggest a system in which mutation acts early in the response on a wide range of substrates and that selection and expansion of high affinity paratopes occurs later.
Insights
Somatic mutation activity in B cells is pronounced early in the immune response to phOx-OVA. Quantifying mutations in one gene underestimates total activity, as diverse V kappa genes are involved early on.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- The immune response involves B cells rearranging V kappa genes to produce antibodies.
- Somatic hypermutation introduces point mutations into antibody genes, enhancing affinity.
- The 2-phenyl-5-oxazolone coupled to ovalbumin (phOx-OVA) model is used to study immune responses.
Purpose of the Study:
- To investigate the timing and breadth of somatic mutation activity in the early immune response to phOx-OVA.
- To determine if focusing on a single V kappa gene underestimates total mutational activity.
Main Methods:
- Comparison of point mutations in V kappa Ox1 genes and related V kappa genes.
- Analysis at two time points after primary immunization with phOx-OVA.
- Detection of somatic mutations in B cells from draining lymph nodes.
Main Results:
- Quantitating mutations in a single gene rearrangement underestimates total mutational activity.
- Pronounced somatic mutation activity occurs early in the response and may decrease later.
- Multiple somatic mutations are detectable in B cells as early as day 7 post-immunization.
Conclusions:
- Somatic mutation acts broadly on diverse V kappa gene substrates early in the immune response.
- Selection and expansion of high-affinity antibodies occur later in the response.
