Complete humoral immunosuppression of mice by rabbit anti-mu antibodies passing the murine placenta.
Female BALB/c mice were immunosuppressed with a series of neonatally initiated rabbit anti-mu serum injections, which eliminated serum IgM and greatly delayed production of antibodies against normal rabbit serum (anti-NRS). Females thus prepared maintained circulating anti-mu levels for several months. Study of the progeny from pregnancies completed during this maintenance period revealed that rabbit anti-mu antibodies readily cross the murine placenta but are not passed in murine colostrum at levels detectable by the technique used. Anti-NRS antibodies actively produced in NRS-injected control females do cross the placenta, but do so only irregularly and poorly; these antibodies may, however, be detected consistently at relatively low levels in colostrum. Suppression of humoral immunoglobulin synthesis in most mice prenatally exposed to anti-mu antibodies by transplacental passage appeared complete, even including loss of the remnant IgG levels which are consistently seen in mice first exposed to anti-mu at birth. The appearance of serum IgG and anti-NRS antibodies along with the complete absence of serum IgM in mice recovering from suppression suggests that active IgM synthesis and secretion may not be a prerequisite for the IgM to IgG "switch". Immune recovery occurred even in completely immunosuppressed mice after anti-mu injections were discontinued; the mechanism of recovery is not certain.
D000818:Animals; D000888:Antibodies, Anti-Idiotypic; D000917:Antibody Formation; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains; D007165:Immunosuppression Therapy; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology*; D010920:Placenta / Q000276:immunology; D011247:Pregnancy; D011270:Pregnancy, Animal; D013997:Time Factors
D000888:Antibodies, Anti-Idiotypic; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains