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A rabbit interleukin-1 (IL-1) inhibitor in inflammatory peritoneal exudate cells was purified to apparent homogeneity. This inhibitor was extracted from exudate cells of the 24-hr stage of caseininduced peritoneal inflammation and purified using isoelectrofocusing (IEF), gel filtration, followed in this order by high-performance liquid chromatography (HPLC) steps with hydroxylapatite and anionic ion exchanger. The purified factor showed a single band on silver-stained SDS-PAGE. This molecule of MW 19,000 and pI 5.5 inhibited the binding of both IL-1α and β to receptors on a thymoma cell line, EL-4 and a B-cell line, 70Z/3. We determined its primary structure by a combination of peptide chemistry and molecular cloning. The inhibitor was synthesized as a precursor composed of 177 amino acids and was processed to a mature molecule of 143 amino acids. The N-terminal amino acid of the mature inhibitor was N-acetyl-methionine residue. The deduced amino acid sequence of the inhibitor showed a 77% homology to the human IL-1 receptor antagonist (IL-1Ra) and essentially the same mode of action as seen with human IL-1Ra. We consider that this inhibitor is a rabbit counterpart of human IL-1Ra, although there are differences with respect to the molecular structure; the N-terminus of the mature rabbit IL-1Ra at a position of nine amino acids downstream from that of human IL-1Ra. [ABSTRACT FROM AUTHOR]

Highly pure polymorphonuclear leucocytes (PMN) were prepared from peritoneal exudate cells which were induced by an i.p. injection of casein into C3H mice and rabbits. The PMN were tested for the production of a lymphocyte proliferation potentiating factor with various stimulations in vitro. In both animal species, the purified PMN from the infiammatory site 3 hr after injection (3-hr PMN) produced the factor upon stimulation with kaolin, while the purified PMN from the lesion 24 hr after injection (24-hr PMN) did not. The 3-hr PMN produced the potentiating factor during a relatively earlier period after in vitro stimulation with kaolin. Protein synthesis inhibitors did not inhibit the factor production, suggesting the release of a preformed factor from 3-hr PMN, The effect of kaolin did not appear to be simply due to its cytotoxicity, because the release was dependent on the metabolism of 3-hr PMN and not parallel with 51Cr-release from the PMN, The factor produced by mouse PMN had an MW of about 15,000–25,000; it consisted of two isoelectrophoretically distinct factors, i.e. pI 9.4 and 5.4, The rabbit PMN factor was slightly smaller (MW ranging between 10,000 and 20,000) than the mouse PMN factor and was composed of three pI species, i.e. 7 2, 5.4, and 4.5. [ABSTRACT FROM AUTHOR]

The effect of inflammation induced by sodium caseinate or aluminum hydroxide on the splenic plaque-forming cell (PEC) response to sheep red blood cells (SRBC) was studied in mice. Direct and indirect splenic PFC responses were enhanced when suboptimal SRBC doses (3 × 106) were injected intra-peritoneally (i.p.) within 9 hr of i.p. inflammatory stimulation; antigen administration 48 hr or more after such stimulation resulted in a slight suppression of the direct response. The inflammation had no effect on the secondary immune response, nor did intra- venous antigen administration enhance the PFC response. Enhancement occurred when early (3 hr), casein-induced peritoneal exudate cells (PEC, consist- ing mostly of neutrophils) were adoptively transferred at the same time as antigen. Treatment of the 3-hr PEC with anti-Thy-I and complement did not decrease their PFC-enhancing capability. Late (96-hr) PEC, consisting mostly of macrophages, manifested only a slight enhancing effect. We suggest that enhancement of the splenic PFC response in the presence of an ongoing inflammation, may be partially attributable to neutrophil function. [ABSTRACT FROM AUTHOR]