Human Coinfection with Borrelia burgdorferi and Babesia microti in the United States

Table 2

Mouse strains.

Strain	Characteristics
BALB/c	Reduced susceptibility to Lyme disease related arthritis; Produce IL-4 and develop a Th2 polarized response to B. burgdorferi; Reduction in IL-4 experimentally demonstrated to increase severity of arthritis; Reduced levels of parasitemia in general when infected with B. microti
C3H/x	Increased susceptibility to Lyme disease related arthritis; Produce IFN-γ and develop a Th1 polarized response to B. burgdorferi; Reduction in IFN-γ correlated with reduced arthritis; Supplementation with recombinant IL-4 correlated with reduced arthritis

Mouse substrains HeJ and HeN were used in different studies. The difference between the two substrains is that the HeN strain is endotoxin sensitive (normal LPS response) and the HeJ strain is endotoxin resistant.