Hey all, I have an immunobiology question for you that is based on data analysis
ID: 58823 • Letter: H
Question
Hey all,
I have an immunobiology question for you that is based on data analysis. I am able to notice the trends in the different tables provided, but I am unsure as to what these trends illustrate in the context of this collected data. I apoogize for the wordiness of this post. I am stuck right now! Any help analyzing this data would be amazing!
Here is some background information:
In an effort to better understand the basis for affinity maturation observed during humoral responses, an investigator knocked out a gene called Odd in one strain of an IgH congenic pair. Thus, the Odd knockouts (-/-) bear the IgHx allotype and the wild-type (wt) bear the IgHz allotype. He immunized these mice with DNP10- KLH and monitored various aspects of the response (Table 1). He also made reciprocal chimeras by adoptively transferring marrow stem cells from Odd KO donors, wild-type donors, or 50:50 mixtures of KO and wt stem cells into lethally irradiated recipients. He immunized these chimeras after reconstitution, and assessed the affinities of IgG antibodies at d21 post immunization (Table 2).
Here are the questions I am supposed to answer:
1. What conclusions do you draw from the data in Table 1?
2. What do you conclude from the reciprocal chimeras (rows 3 and 4) in Table 2?
3. What additional conclusions does the mixed chimera afford?
Overall: Summarize what this data in toto tell you about Odd, and describe a possible experiment you would preform to further investigate this gene.
Explanation / Answer
1. The important conclusion from the table is KO chimera has no effect on the IgM, IgG production when compared to the wild type. Ka of an antibody is known as association or equilibrium constant. It will give the affinity of the antibody towards the antigen, if Ka > 107 M-1 antibodies will have high affinity towards the antigen. In the wild type, DNP immunization is decreasing the affinity of antibodies, but the odd KO chimera is partially restoring the affinity towards DNP.
2. In the reciprocal chimera experiment KO has no effect when it is introduced into the WT recipient. This suggest that host factors do not play a role in rescuing this knock out. The results are same as in the experiments in row 1 and 2.
3. When you introduce 50:50 mix chimeras into a WT recipient, both the chimeras produce the antibodies with same affinity towards the DNP.
The overall conclusion could be that KO chimeras produces antibodies having slightly more affinity towards DNP compared to the wildtype and this is function is compromised when you give in the 50:50 into a WT recipient.