The inflammatory response to lymph node cells from adjuvant-diseased rats: late changes in local and systemic leucocyte counts in the Wistar strain

Abstract

In contrast to previous studies on Lewis rats, lymph node cells from Freund's complete adjuvant (FCA)-treated Wistar rats did not stimulate granuloma formation when injected into into subcutaneous sponge implants in syngeneic recipient rats. No morphological differences were observed between the cell suspensions from FCA-treated and incomplete adjuvant (FIA)-treated control animals. Following transfer of both types of lymph node cells, granuloma exudate neutrophil counts were high after 3 days and rapidly declined thereafter, while exudate monocyte/macrophage counts slowly increased. In the control group of recipient rats, this latter increase was associated with increased peripheral blood monocyte counts by day 11, whereas in rats receiving FCA-treated cells the only significant changes in blood cells increased total leucocytes on day 3 and increased neutrophil counts on day 7. Another difference between FIA and FCA groups was that exudate small lymphocyte counts in the former group fell rapidly between days 3 and 7, while in the latter group this fall was significantly slower. It was concluded that these leucocyte changes, both local and systemic, reflect certain more sustained cell stimulating effects of FCA-treated lymph node cells when compared with FIA-treated cells, particularly on neutrophils and small lymphocytes. In addition, in rats which received FIA-treated lymph node cells, significant correlations existed between exudate and peripheral blood small lymphocyte counts on day 3 and between both exudate monocyte/macrophage and neutrophil counts and granuloma weight on day 7. No significant correlations were found following injection of FCA-treated cells. It was concluded that FCA treatment stimulates the appearance of suppressor functions of lymph node cells from Wistar rats, which together with their other more sustained inflammatory activities result in the net failure to observe significant changes in or correlations between leucocyte counts and granuloma formation. These findings may shed light on the relative sinsensitivityof Wistar rats to the induction of adjuvant arthritis.