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The attachment of the terminal components of complement on cell membranes
Micron, 1977, Vol. 8: 237. Pergamon Press. Printed in Great Britain.
The a t t a c h m e n t o f the t e r m i n a l c o m p o n e n t s o f c o m p l e m e n t on cell m e m b r a n e s R. D O U R M A S H K I N
Clinical Research Centre, Harrow, Middlesex, HA1 3UJ, England One of the pathways of the lytic attack of complement on the cell membranes is b y means of reactive lysis, in which the complement components C5 and C6 are activated in the aqueous phase and attach directly to sensitive membranes. With the addition of C7, a stable C5,6,7 complex is formed. With the addition of C8 and finally C9, the complex results in cell m e m b r a n e damage and lysis of the cell at the C9 stage. By the use of purified components, it was p~ssible to visualise these stages of the action of complement by electron microscopy. The attachment of C5,6 was evanescent and broken
237
up during the process of negative staining. The C5,6,7 complex appeared as a radiating flower shaped molecule on the m e m b r a n e surface edge with the apex inserted into the membrane. A similar structure was seen in the C5-8 complex. However, on the addition of C9, the C5-9 complex appeared to be completely different to the C5-8 complex and identical to the structure of the complement holes or lesions previously observed using whole complement. The interpretation and significance of the above observations was presented.
The a t t a c h m e n t o f the t e r m i n a l c o m p o n e n t s o f c o m p l e m e n t on cell m e m b r a n e s R. D O U R M A S H K I N
Clinical Research Centre, Harrow, Middlesex, HA1 3UJ, England One of the pathways of the lytic attack of complement on the cell membranes is b y means of reactive lysis, in which the complement components C5 and C6 are activated in the aqueous phase and attach directly to sensitive membranes. With the addition of C7, a stable C5,6,7 complex is formed. With the addition of C8 and finally C9, the complex results in cell m e m b r a n e damage and lysis of the cell at the C9 stage. By the use of purified components, it was p~ssible to visualise these stages of the action of complement by electron microscopy. The attachment of C5,6 was evanescent and broken
237
up during the process of negative staining. The C5,6,7 complex appeared as a radiating flower shaped molecule on the m e m b r a n e surface edge with the apex inserted into the membrane. A similar structure was seen in the C5-8 complex. However, on the addition of C9, the C5-9 complex appeared to be completely different to the C5-8 complex and identical to the structure of the complement holes or lesions previously observed using whole complement. The interpretation and significance of the above observations was presented.