MCPs elicit antibodies to cryptic epitopes of gp120.

<p>(A) Binding of MAb 11A8 to gp120 is not inhibited by antisera to gp120. Competition for gp120_MN binding of biotinylated MAb 11A8 and murine sera was evaluated in ELISA as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0008555#s4" target="_blank">Materials and Methods</a>. All competing sera were obtained from C57Bl/10 mice prior to immunization (preimmune), from mice immunized with 426–441 MCP (130, 000) or with rgp120MN (550, 000). Titers of sera antibodies recognizing gp120 are listed in parenthesis. Results are expressed as % inhibition of biotinylated 11A8 binding to gp120 by competing antibodies. (B) HIVIG does not inhibit the binding to gp120 of murine antibodies elicited by MCPs 419–439, 363–384 or 105–117. Competition between HIVIG and anti-MCP sera for binding to gp120 was assayed by ELISA as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0008555#s4" target="_blank">Materials and Methods</a>. Gp120 was incubated with HIVIG at the indicated concentrations and the binding of anti-MCP sera (colored lines) from C3H/HeJ mice (anti-MCPs 105–117 and 363–384), C57Bl/10 mice (419–439 MCP) or of HIVIG (shown as black line) was determined. Results are expressed as absorbance at 405 nm.