The effect of intravascular complement activation and brief episodes of hypoxia on protein in bronchoalveolar lavage fluid in C5 sufficient and deficient mice.

Our earlier investigations indicated that systemic complement activation with iv cobra venom factor (CVF) or infused zymosan-activated rabbit plasma or rabbit C5a does not significantly increase bronchoalveolar lavage albumin in rabbits (Am Rev Respir Dis 1982; 125:335-340); but that complement activation due to CVF combined with a brief episode of hypoxia increases lavage albumin and is associated with the presence of neutrophils for its expression (J Clin Invest 1985; 75:902-910). In order to determine if intravenous CVF and hypoxia cause similar alterations in mice, and to investigate the time course of the response as well as the importance of C5 fragments to the process, we challenged the B10.D2/nSn strain of C5 sufficient mice (C5+) and the congenic B10.D2/oSn strain of C5 deficient mice (C5-) with intravenous CVF, 15 min of 12% oxygen, or CVF followed by hypoxia. Neither C5+ nor C5- mice had significant increases in lavage protein after either CVF or hypoxia. However, the combined insults significantly increased lavage protein in C5+ but not C5- mice; polyacrylamide gel electrophoresis showed increased amounts of proteins of low and high molecular weights in lavage fluid from the C5+ strain. While the time course of abnormalities in mice was different from that in rabbits, both meclofenamate pretreatment and neutrophil depletion attenuated the increases in lavage protein after the combined insults in both animal species. Infusion of prostaglandin E2 (PGE2) with CVF in the C5+ mice also led to significant increases in lavage protein. We conclude that in mice, intravenous complement activation, as an isolated event, does not cause a significant increase in lavage protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the evolving histopathology of early and late cutaneous and asthmatic responses in rabbits after a single antigen challenge.

Histopathologic changes during the immediate cutaneous response (ICR) and late cutaneous response (LCR) to antigen challenge in allergic humans include dermal edema in the ICR (15 to 30 minutes) followed by increasing cellular infiltration in the LCR (6 hours and more). No description of the evolving histopathologic changes that occur during an immediate asthmatic response (IAR) followed by a late asthmatic response (LAR) exists in either clinical studies or animal models. We examined cutaneous and pulmonary histopathology at 1/2, 6, 24, and 48 hours as well as 7 days after simultaneous intradermal and aerosol antigen challenge of rabbits immunize with Alternaria tenuis extract. Nonimmunized rabbits challenged with Alternaria tenuis extract and immunized rabbits challenged with normal saline served as controls. Immediate wheal and flare responses followed by a LCR were seen in immunized but not control animals. Pulmonary function tests documented immediate and LAR in immunized but not control animals. Thirty minutes after antigen challenge of sensitized animals (ICR and IAR), both dermal sites and large airway submucosal sites had interstitial edema and vessel dilatation while small airways were essentially normal. At 6 hours after challenge, the dermal and large airway submucosal sites of immune animals (LCR and LAR) demonstrated a moderate mixed leukocyte infiltrate as well as residual edema. Additionally, bronchioles and pulmonary vessel adventitia from these responding animals had an intense and widespread leukocyte infiltration. At 24 and 48 hours, immune challenged animals but not controls had a marked mixed cellular infiltrate near skin vessels and near the bronchioles and pulmonary vessels with little or no residual interstitial edema. At 7 days, three of four animals showed resolution of the inflammation while the fourth showed minimal residual changes. Morphometric analysis of airway inflammation substantiated these qualitative observations and demonstrated that the granulocytes around airways of immune rabbits were a mixture of neutrophils and eosinophils at 6 hours, but were predominantly eosinophils at 48 hours. Immunofluorescent studies of skin and lung tissue did not demonstrate any granular or linear deposition of immunoglobulin or complement at the sites of inflammation, however, fibrin deposition was noted in the skin and lungs of immune rabbits. These observations show that immunized rabbits challenged with antigen develop cutaneous and pulmonary inflammation.(ABSTRACT TRUNCATED AT 400 WORDS)