Methods and compositions for treatment, diagnosis, and prevention of a virus comprise administering to a patient antibodies which react with regions of viral proteins and result in neutralization of infectivity and inactivation of functionally essential events in the life cycle of the virus. The antibodies recognize viral epitopes which fail to elicit an immune response in man when encountered through infection or naturally through the environment. In a preferred embodiment, the invention provides compositions and methods useful in the treatment and diagnosis of human immunodeficiency virus (HIV) infections. The present invention is also directed to chemical conjugates (herein referred to as MDP) adjuvant microparticle-antigen conjugates) that have a muramyl dipeptide backbone crosslinked into a microparticle capable of binding to the cell surface of Antigen Presenting Cells (APCs), to which is covalently attached one or more molecules having a reactive carbonyl group (i.e. an aldehyde and ketone group that is capable of reacting with amino groups to form an imine or Schiff base) on either the MDP adjuvant microparticle or on the antigen whereas the antigen is one or more glycoproteins, proteins, polypeptides or peptides that are capable of eliciting an immune response when covalently attached to the MDP microparticle adjuvant. Also disclosed are methods for making the conjugates, using the conjugates to elicit an immune response in a mammal.