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[Humoral and cellular immunity in children vaccinated with oral B.C.G. (author's transl)]
Insights
Oral vaccination with fresh BCG in young children did not boost antibody or immunoglobulin levels. However, it did enhance cellular immunity, making 60% of non-reactor children responsive to PPD. Further studies are ongoing.
Area of Science:
- Immunology
- Pediatrics
- Vaccinology
Background:
- Bacille Calmette-Guérin (BCG) vaccination is crucial for preventing tuberculosis.
- Oral BCG administration is being explored as an alternative to intradermal vaccination.
- Assessing immune responses in young children post-oral BCG is vital for vaccine efficacy.
Purpose of the Study:
- To evaluate the humoral and cellular immune responses in young children after a single oral dose of fresh BCG (Moreau strain).
- To determine if the oral BCG vaccination schedule stimulates antibody production or alters immunoglobulin and lymphocyte levels.
- To assess changes in PPD responsiveness and in vitro cellular immunity markers.
Main Methods:
- Investigated 23 children aged 1-5 years, initially non-reactive to purified protein derivative (PPD).
- Administered a single oral dose of 100 mg fresh oral BCG (Rio de Janeiro, Moreau strain).
- Performed immunological tests before and 70 days after vaccination, including PPD skin tests, serum immunoglobulin levels, lymphocyte counts, and leukocyte migration inhibition assays.
Main Results:
- The vaccination schedule did not stimulate anti-PPD antibody production or significantly alter serum immunoglobulin and blood lymphocyte levels (T, T-active, B cells).
- Approximately 60% of vaccinated children converted to PPD responsiveness (10 mu).
- All children demonstrated positive reactions in in vitro leukocyte migration inhibition assays for PPD.
Conclusions:
- A single oral dose of fresh BCG (Moreau strain) was insufficient to induce a robust humoral immune response in young children.
- The oral BCG vaccination regimen enhanced cellular immunity, indicated by increased PPD responsiveness and positive leukocyte migration inhibition tests.
- New vaccination schedules for oral BCG are being developed to potentially improve immunogenicity.
Abstract:
The humoral and cellular immunity of 23 children with ages between 1 and 5 years, nonreactors to 10 mu of PPD, were investigated after oral vaccination with one dose of 100 mg of fresh oral BCG, Rio de Janeiro strain (Moreau strain). The tests performed shortly before and 70 days after vaccination showed that the schedule used was neither sufficient to stimulate the production of antibody anti-PPD, nor to change the levels of serum immunoglobulins and T, T-active and B blood lymphocytes. However, about 60% of the children became responsive to 10 mu of PPD after treatment and all gave positive reactions to PPD on "in vitro" assays of leukocyte migration inhibition. New schedules for oral vaccination with fresh BCG are in progress in our laboratory.