immunology- complement system and MHC

Complement components are synthesized in the body by several cells

hepatic parenchymal

cells, monocytes, macrophages and intestinal epithelium.

C5a attracts phagocytic cells, mainly polymorphs

Chemotaxis

particles are

phagocytosed much more efficiently in the presence of C3b bound on their surfaces

Opsonization

C3a and C5a can produce degranulation of mast cells

Anaphylatoxins

a portion of the short arm of human

chromosome 6

major

histocompatibility gene complex,

Regions B, C and A

antigenic specificities of class I MHC surface molecules.

Region D

antigenic specificities of class II MHC surface molecules

The region between D and B

certain complement components (C2, C4, factor

B)

MHC l-restriction

Tc cells (cd8) recognition of MHC l and antigen on the surface of graft cells, tumour cells or virus infected cells

Class I MHC–antigens

glycoproteins and include HLA-A, HLA-B, and HLA-C.

Class II MHC-antigens

glycoproteins that includes

HLA- DP, HLA-

DQ and HLA-DR.

antigen presenting cells (APCs) with MHC ll

monocytes,

macrophages, dendritic cells in lymph nodes, Langerhans cells in skin and B lymphocytes.

MHC ll restriction

(Th) (CD4) will recognize foreign antigen on the surface of APC only if they

are associated with class II MHC molecules

HLA-B27

ankylosing spondylitis