I performed an ab elisa in mice vaccinated with DNA and gp120 candidate HIV vaccine. Screening the levels of IgG, IgG1 IgG2a IgG2b IgM and IgD in serum. I was wondering if the presence of IgM is due to the fact that it is a T helper independent? Or is there another explanation?
Did you measure antibody response at different time points, i.e. early vs. late? Did you detect other antibodies in your ELISA screen? Antibodies take weeks to develop and class switching must occur before specific IgM levels will fall and other immunoglobulin classes will rise. Furthermore, IgM is less specific with better binding affinity, so you may also be detecting non-specific IgM (Are you optimizing your own ELISA or is it commercial? Are your mice reared in sterile environments free of other infections?). I am not familiar with HIV in particular but you should browse research papers on immunological responses to HIV (ideally studies from other vaccine trials) and examine the time frame for different classes to become present.
Did you measure antibody response at different time points, i.e. early vs. late? Did you detect other antibodies in your ELISA screen? Antibodies take weeks to develop and class switching must occur before specific IgM levels will fall and other immunoglobulin classes will rise. Furthermore, IgM is less specific with better binding affinity, so you may also be detecting non-specific IgM (Are you optimizing your own ELISA or is it commercial? Are your mice reared in sterile environments free of other infections?). I am not familiar with HIV in particular but you should browse research papers on immunological responses to HIV (ideally studies from other vaccine trials) and examine the time frame for different classes to become present.
I had mice vaccinate with 3 types of HIV candidate vaccines. at endpoint I measure Different kinds of Ab, (IgG1, IgG2a, IgG2b, IgG total, IgM and IgD.,) I was surprised that naive group had reletaviley similar amount of IgM., and since these are pathogen free mice, I did not expect to see similar IgM response in naive groups,.and also in vaccinated groups,.,.because B cells will have undergone differentiation and class switching in vaccinated groups,,.hence loosing the IgM,.
Are you talking about antigen-specific or total antibodies? I would not expect total antibody levels to differ signicificantly after vaccination. Also, are you getting the same positive or negative results? Depending on your schedule, I would not expect to detect any antigen-specific IgM at endpoint, since all antibodies should already have class switched.
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