The genome is arranged so that both of the ends contain the genes responsible for evading the defenses from the immune system of the host which is only activated in the extracellular portion. These receptors are able to be stopped by cytokine and chemokine secretion by blocking the cytokine and chemokine found extracellularly. This is the process responsible for attachment and entry of the virion into the host cell. Because of the large size of the genome, it makes the virus more likely and capable to fight back against the immunes system defenses. Out of all of the poxviruses, CPXV has the most cytokine responses that fight back against the immune system. It encodes cytokine receptors such as TNF, CrmB, CrmC, CrmD, and CrmE proteins. Another set of receptors that CPXV have are lymphotoxins such as IL-1ß, IFN-y, IFN 1, β-chemokines, and IL-18. However, not all of the receptors of CPXV are still not known. CPXV also encodes four tumor necrosis factors (TNF) and lymphotoxin which are the biggest group of homologous receptors for the virus. These receptors play a crucial role that are involved with the immune system.
