Interferons::
Interferons are small proteins released by the certain body cells and mostly provide protection against viral infections they are not virus specific but are host specific i.e interferons of mice cannot protect human and vice versa
There are three classes of interferons (INF) termed INF-a INF-B and INF-y INF-a and INF-B are produced by macrophages fibroblasts endothelial cells osteoblasts etc
INF-y is produced mainly by antigen -activated T lymphocytes in inflammatory and auto immune conditions
Interferons promotes the activation of leucocytes accelerate formation of leucocytes from bone marrow and also modulate cytokine synthesis
Presently interferons are also used clinically to treat certain cancers viral infection leprosy leish maniasis and multiple sclerosis
Phagocytosis::
It is a process of engulfing killing and digesting the foreign organisms by neutrophils and macrophages the engulfing takes place by cytoplasmic extension towards the foreign particles Engulfed foreign particle is called phagosome which fuses with lysosome and forms phagolysome lysosomes liberate free radicals which have potent cell killing ability the destroyed bacterial material is digested and indigestible residual material is removed by exocytosis Thus -phagocytosis takes place in following three phases:
(1) Foreign particle (Antigen) adheres to macrophages this requ complement proteins and antibodies coating the antigen (opsonisation)
(2) Engulfing- by formation of pseudopods (Antigen internalization)
(3) Destruction of antigen : (Antigen procuring and antigen presentation) It includes lysosomal binding and destruction of antigen by lysosomes and their exocycosis of indigestible material
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