| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1988: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
The 28,000 mw active fragment of guinea pig Hageman factor (beta-HFa), injected intradermally, induces an increased vascular permeability. To determine if prekallikrein (PK) and kallikrein(Kal) participated in the permeability induced by beta-HFa, circulating PK was depleted by intra-arterial injections of anti-PK antibody. This resulted in about 80 percent diminution in the permeability response to -HFa. Soybean trypsin inhibitor, injected simultaneously with beta-HFa, inhibited the permeability response by more than 90 percent. The soybean inhibitor blocked the activity of Kal, but did not inhibit the amidolitic capacity of beta-HFa. The permeability activity of beta-HFa was augmented 10-fold by simultaneous injection of a synthetic kinin potentiator, and was almost completely inhibited by the simultaneous injection of a kinin destroying enzyme. These results indicated that the cascade system indeed worked in vivo possessing the potential permeability enhancement capacity.
Guinea pig
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alpha_2-macroglobulin which is not only a major circulating inhibitor of tissue destructive pathogenic proteases but also of beta-HFa was immunologically depleted from three animals. Duration of the permeability reaction caused by beta-HFa was prolonged twice as long as the control, indicating a presence of negative feedback regulation of the cascade system via the circulating protease inhibitor.
Activation of the Hageman factor-kallikrein-kinin system by tissue destructive proteases derived from invasive microbe was investigated. Nine of the eleven proteases examined including a novel cysteine protease, 73k protease of Serratia marcescens, activated Hageman factor in vitro as well as in vivo resulting in the vascular permeability enhancement. Three proteases of the positive nine also activated prekallikrein directly. Remaining two proteases which activated neither HF or PK generated bradykinin-like molecule from high-molecular weight kininogen directly.
These results suggested an important role of the Hageman factor dependent permeability system in host defence especially against tissue destructive proteases derived from invasive microbe. Less
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