Hi
I'm going to administer an intramuscular injection of alum-absorbed diphtheria toxoid (twice with 3 weeks intervals) to Sprague-Dawley rats and I'm going to assay their effects two weeks after the second administration, but I can't find an appropriate dosage (limit of flocculation)...
The first group constituted up to 15 per cent of total blast cells. The staining was sometimes limited to small stippled dots over the nucleus or it was uniformly distributed
throughout the cytoplasm. Urso and Makinodan (1963) consider the stippled pattern to
correlate with the first appearance of antibody. This interpretation may well be correct
but we have certain reservations about the true intranuclear location of the antibody.
The cytoplasmic staining varied in intensity in different cells but it was particularly bright
in mitotic cells, which suggests that there was a progressive build-up of the antibody concentration in the cells as they progressed through the DNA synthetic and the G2 period
towards mitosis.
The blast cells then divide giving rise to cells of the intermediate type. These cells became labelled with [3H]T 4-6 hours after the injection of the isotope and their mean grain
count was about half the mean of the counts over the cells labelled at 1 hour which is the
order to be expected for progenitor and daughter cells. Occasionally these cells modified
their morphology very rapidly to assume the form of the mature plasma cell within 4-6
hours. In one experiment it was found that 70 per cent of the intermediate cells were
labelled 12 hours after a single dose of [3H]T, whilst only 22 per cent of the mature plasma
cells were labelled. It is possible that some of the intermediate cells did not differentiate
at this stage and entered a further division cycle. From the study of the post-divisional cells
formed during a 12 hour period it is apparent that the rate of change in morphology, i.e.
the change in nuclear cytoplasmic ratio and in the position of the nucleus in the cell is
variable. Cells with small eccentric nuclei were occasionally observed to be labelled within
this time which suggests that the morphology of the post-divisional cell is influenced by
factors other than its age. An unsolved problem is the nature of the pre-divisional cell
that gives rise to the small lymphocyte-like cell containing antibody. The majority of
antibody-containing mitotic cells were almost as large as blasts but occasionally much
smaller dividing cells have been observed and these might possibly have been the precursors of the small lymphocyte-like cells.
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