Spontaneous Development of IgM Anti-Cocaine Antibodies in Habitual Cocaine Users: Effect on IgG Antibody Responses to a Cocaine Cholera Toxin B Conjugate Vaccine … Original source: Spontaneous Development of IgM Anti-Cocaine Antibodies in Habitual Cocaine Users: Effect on IgG Antibody Responses to a Cocaine Cholera Toxin B Conjugate Vaccine