NF-kappaB is implicated in lymphocyte development, maturation, proliferation and 
survival. This inducible transcription factor is widely expressed by virtually 
all cell types. In mammals, the genes rela, relb, crel, nfkappaΒ1, and nfkappaB 
encode the five NF-kB protein family members RelA (p65), RelB, c-Rel, p50, and 
p52, respectively, which form homo- and heterodimeric DNA-binding complexes 
capable of regulating target gene transcription of specific biological responses 
differentially. NF-kappaB regulates the expression of a wide variety of genes 
that play critical roles in innate and adaptive immune responses, is strongly 
linked to the inhibition of apoptosis, and contributes to tumor growth, 
metastasis, and chemoresistance. Parasites have targeted several parts of the 
NF-kappaB pathway, allowing them to interfere with the transcription of immune 
response genes. The biology of different parasites is critical in influencing 
the patterns and kinetics of NF-kappaB activity and thereby the development of 
subsequent immune responses.