1. A researcher purified mu heavy chains from two inbred* strains, called C3H and A/J. She immunized mice from each strain with the other's mu chains, yielding C3H anti-A/J mu and A/J anti-C3H mu. She tested each antiserum against normal serum immunoglobulins from the sources shown:
Precipitate with serum from:
Antiserum C3H A/J (C3H X A/J)F1
C3H anti-A/J mu - + +
A/J anti-C3H mu. + - +
She next attached fluorescein to the C3H anti-A/J mu, and rhodamine to the A/J anti-C3H mu. These compounds fluoresce (glow) under UV light: fluorescein glows green and rhodamine glows red. She added these reagents to B-cells from each strain and from F1's, waited awhile, washed away the anti-mu reagents. Finally, she looked at the cells under a special microscope that shines UV light on the sample, so that if one, the other, or both reagents bound to a cell, it will glow either red, green, or red and green. The proportion of B cells in each sample falling into each such category are shown:
Proportion of B cells in each category from:
cell that glow: C3H A/J (C3H X A/J)F1
green only 0% 100% 50%
red only 100 0 50
red and green 0 0 0
From the first table, what do you conclude about mouse m genes and their expression?
From the second table, what do you further conclude?
* "inbred" means that these mice have been backcrossed (child x parent or brother x sister) more than 20 times so that within a given "strain," there is homozygosity at all loci.
2. You have two IgA antibodies made by mouse myeloma cells: One called M315 that binds DNP; and one called T15 that binds PC. [The PC hapten is structurally different from DNP]. You synthesized a peptide of three lysines with DNP on one end and PC on the other: DNP-lys-lys-lys-PC. You set up nine tubes containing this compound, then added different combinations of the whole antibodies at 1 mM or their Fab fragments at 10mM.
Notice that the last column has been left blank - that's your job: In your journal, list the tube numbers, and next to each tube number write a "yes" if a precipitate would be observed and "no" if it would not. Explain your reasoning.
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Details of B-cells Immunology
A B cell has internalized a toxin that contains the epitope recognized by its surface Ig. Describe how this cell would be activated, the cellular and molecular interaction(s), and the various steps and factors leading to an appropriate immune response to clear the toxinView Full Posting Details