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Comparison of the immune responses in children vaccinated with three strains of BCG vaccine
V Vijayalakshmi1, K J Murthy, S Kumar
1Bhagvan Mahavir Medical Research Centre, Mahavir Marg, Hyderabad.
Insights
This study compared cellular responses in children vaccinated with Japan-BCG, Glaxo-BCG, and Madras-BCG. All three BCG strains demonstrated similar capacities for inducing cellular immune responses in infants.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Bacille Calmette-Guérin (BCG) vaccination is crucial for preventing tuberculosis (TB) in children.
- Different BCG strains exist, potentially influencing vaccine efficacy and cellular responses.
- Evaluating strain-specific cellular immunity is vital for optimizing TB prevention strategies.
Purpose of the Study:
- To compare the specific cellular immune responses induced by three different BCG vaccine strains: Japan-BCG, Glaxo-BCG, and Madras-BCG.
- To assess both in vivo (induration diameter) and in vitro (leukocyte migration inhibition test - LMIT) parameters following vaccination.
- To determine if significant differences exist in the immunogenicity of these BCG strains in infants.
Main Methods:
- A randomized study involving 300 healthy infants, with 100 vaccinated with each BCG strain.
- Measurement of vaccination site induration diameter at 6 weeks post-vaccination.
- In vitro leukocyte migration inhibition test (LMIT) performed at 3 and 6 months post-vaccination using PPD tuberculin antigen.
Main Results:
- Glaxo-BCG group showed a significantly larger mean induration diameter compared to Japan-BCG and Madras-BCG (p < 0.05).
- Mean LMIT values were comparable across all three BCG strain groups.
- No significant correlation was observed between in vivo induration and in vitro LMIT results.
- High percentages of children showed positive LMIT responses by 6 months across all groups (91-95%).
Conclusions:
- Despite variations in local skin reactions, the three BCG strains (Japan, Glaxo, Madras) induced similar overall cellular immune responses in infants.
- The study suggests no major differences in the capacity of these BCG strains to elicit cellular immunity.
- Further research may explore long-term efficacy and specific immunological profiles related to each strain.
Abstract:
The present study was conducted to evaluate and compare the specific cellular responses of children vaccinated with three different strains of BCG. The study comprised of normal children with normal weight and normal general responses (PHA) to in vitro leukocyte migration inhibition test (LMIT). The three strains of BCG under study were Japan-BCG, Glaxo-BCG and Madras-BCG. One hundred children were selected at random from each group. The mean ages of these infants were 9.9 +/- 9.5, 9.8 +/- 7.6 and 9.8 +/- 8.3 weeks, respectively. Six weeks after vaccination, the diameter (in mm) of induration at the vaccination site was measured. Three months after vaccination, in vitro LMIT was performed against PPD tuberculin antigen. This test was done again after 3 months in all the children who tested negative. The mean value of the diameter of the Glaxo-BCG group (10.0 +/- 13.5 mm) was significantly higher (p < 0.05) than the mean values of Japan-BCG (9.10 +/- 3.9 mm) and Madras-BCG (8.38 +/- 4.1 mm). The mean LMI values were similar in all the three groups. There was no correlation between the in vitro and in vivo parameters. The number of children positive to LMI (PPD) were 59, 58 and 63, for the Madras, Japan and Glaxo-BCG groups, respectively. A total number of 91, 91 and 95 were positive to LMIT at the end of 6 months after BCG in the Madras, Japan and Glaxo-BCG groups, respectively. The observations suggested that there were no major differences between the three strains of BCG in their capacity to induce cellular responses.