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Antiphosphocholine antibodies found in normal mouse serum are protective against intravenous infection with type 3

D E Briles, M Nahm, K Schroer

    The Journal of Experimental Medicine
    |March 1, 1981
    PubMed

    Insights

    Normal mouse sera (NMS) containing antiphosphocholine (PC) antibodies protect against Streptococcus pneumoniae infection. Mice lacking these antibodies are susceptible, but can be protected by NMS or specific IgM antibodies, highlighting PC antibody importance.

    Area of Science:

    • Immunology
    • Microbiology
    • Infectious Disease

    Background:

    • Antiphosphocholine (PC) antibodies in normal mouse sera (NMS) are crucial for defense against encapsulated bacterial pathogens.
    • Streptococcus pneumoniae, a leading cause of bacterial infections, possesses a polysaccharide capsule that can evade immune responses.

    Purpose of the Study:

    • To investigate the protective role of antiphosphocholine (PC) antibodies against intravenous infection with Streptococcus pneumoniae type 3.
    • To determine the susceptibility of mice lacking anti-PC antibody production to S. pneumoniae infection.
    • To evaluate the efficacy of exogenous anti-PC antibodies in conferring protection.

    Main Methods:

    • Intravenous infection model using encapsulated strain WU2 of Streptococcus pneumoniae type 3.
    • Utilized mice with suppressed anti-PC antibody production (anti-T-15 idiotype) and mice with the xid gene (CAB/N mice).
    • Administered normal mouse sera (NMS) or purified IgM hybridoma anti-PC antibody for protection studies.
    • Employed PC-containing immunoabsorbents to remove protective antibodies from NMS.

    Main Results:

    • Normal mouse sera (NMS) conferred significant protection against S. pneumoniae WU2 infection.
    • Mice lacking anti-PC antibody production (due to anti-T-15 idiotype suppression or xid gene inheritance) exhibited high susceptibility to WU2 infection.
    • Mice inheriting the xid gene were successfully protected by NMS from normal mice or by specific IgM hybridoma anti-PC antibody.
    • The protective effect of NMS was abrogated by absorption with PC-containing immunoabsorbents, confirming the role of anti-PC antibodies.

    Conclusions:

    • Antiphosphocholine (PC) antibodies are essential for protection against intravenous infection with encapsulated Streptococcus pneumoniae type 3.
    • The xid gene and T-15 idiotype suppression impair anti-PC antibody production, leading to increased susceptibility to S. pneumoniae.
    • Exogenous administration of anti-PC antibodies, including specific IgM hybridoma antibodies, can restore protection in susceptible mice.

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