P2G12 is a human IgG1 class monoclonal antibody (MAb) which has been expressed in tobacco plants (referred to as "P2G12" to indicate plant origin). The parent molecule ("2G12") is one of a handful of MAbs with potent neutralising activity against HIV and has been produced by CHO cell fermentation (referred to as "C2G12" to indicate CHO-cell origin). A number of studies have demonstrated that passively infused monoclonal antibodies can protect against an intravenous challenge by the infectious SHIV reagent in rhesus macaques. Furthermore, HIV neutralising MAbs can affect transmission and subsequent disease course after vaginal SHIV-challenge in macaques In studies in humans, the MAb C2G12 was safe after repeated intravenous infusions to asymptomatic HIV-1-infected individuals . Similarly, another MAb 4E10 was safe after intravenous infusions, alone and in combination with other MAbs including C2G12, to HIV-1-infected individuals These studies prepared the way for the introduction of these MAbs for human immunoprophylaxis against HIV infection and indeed new generation anti-HIV MAbs are currently being advanced in prophylactic and therapeutic children and adult clinical trials with children and adults With respect to the MAb 2G12, in a number of human clinical trials, 4 to 16 infusions of C2G12 were given in doses ranging from 0.5g to 1g alone or in combination with other MAbs. The safety results from these studies were reassuring with minimal adverse drug reactions observed. Those that were reported were of myalgia and arthralgia. In a recently conducted study, P2G12 was safe to use when administered intravaginally at a concentration of 7, 14 and 28mg/ml.