Circumsporozoite protein (CS) is a leading vaccine antigen for falciparum malaria. but is highly polymorphic in natural parasite populations. The factors driving this diversity are unclear. but non-random assortment of the T cell epitopes TH2 and TH3 has been observed in a Kenyan parasite population. https://www.roneverhart.com/Apple-Watch-Ultra-2-GPS-Cellular-49mm-Titanium-Case-with-Blue-Black-Trail-Loop-S-M-MRF53LL-A/