ITIH4 and infection: In a gp120-capture ELISA, D1/85.16 cl.23 and CC1/85 cl.6 gp120s were the most reactive with MAb 17b (Fig. 5C), which is in marked contrast to the infection-inhibition experiments where D1/85.16 cl.23 and CC1/85 cl.6 were the clones least sensitive to 17b and the related 48d MAb (Fig. 6A,B).