Intrathecal injection (i.t.) of gp120 caused mechanical allodynia in mice. Threshold of mechanical pain in the hind paw was measured by von Frey testing. Numbers of animals used in each group: boiled gp120IIIB, 11 mice; gp120Bal: 6 mice; gp120IIIB, 6 mice (*, p<0.05, ***, p<0.001, #, p>0.05, all vs. the control group; two-way ANOVA; outliers that were larger than 2 standard deviations were excluded). i.t. injections were indicated by arrows.