HIV attaches to CD4 cells and enters them. Inside, HIV makes copies of itself that will help the virus invade the body. CD4 cells are killed or disabled during this process of HIV replication. Decreases in CD4 cells lead to a weakened immune system. When CD4 cell counts become very low, the body is unable to defend itself, and HIV infection develops into AIDS. The protein used in this study, CD4-IgG2, may be able to attach to HIV and inactivate it so that it cannot enter CD4 cells. This is an early study to examine CD4-IgG2 as a possible treatment for HIV in children.