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Organized lymphatic tissue (BALT) in lungs of rhesus monkeys after air pollutant exposure
Reinhard Pabst1, Lisa A Miller2, Edward Schelegle2
1Institute of Immunomorphology, Centre of Anatomy, Medical School of Hannover, Hannover, Germany.
Insights
Bronchus-associated lymphoid tissue (BALT) in rhesus monkeys increases with age and is significantly elevated by ozone exposure, but not by house dust mite exposure. This suggests ozone is a key environmental factor influencing BALT development.
Area of Science:
- Immunology
- Pulmonary Medicine
- Toxicology
Background:
- Bronchus-associated lymphoid tissue (BALT) presence and size vary with age in humans, being common in young children but absent in healthy adults.
- Environmental factors like gases and allergens may influence BALT.
- Understanding BALT development in response to environmental stimuli is crucial for respiratory health research.
Purpose of the Study:
- To investigate the influence of age and environmental exposures (ozone and house dust mite) on BALT in rhesus monkeys.
- To determine if ozone or house dust mite exposure affects BALT formation and size.
- To compare the effects of different environmental exposures on BALT development.
Main Methods:
- Histological screening of rhesus macaque lungs.
- Exposure of monkeys to filtered air, ozone, house dust mite (HDM), or a combination for varying durations (2 to 36 months).
- Quantification and localization of BALT, with attention to lymphocyte accumulation.
Main Results:
- BALT was age-dependent in monkeys housed in filtered air, increasing with duration of exposure.
- No significant increase in BALT was observed after house dust mite (HDM) or HDM + ozone exposure.
- Ozone exposure alone led to significant increases in BALT, particularly with lymphocyte accumulations in the periarterial space, compared to all other groups.
Conclusions:
- BALT development in rhesus monkeys under filtered air is age-dependent.
- Ozone exposure significantly increases BALT compared to HDM exposure or filtered air.
- Ozone is a potent environmental factor influencing BALT formation in the primate lung.
Abstract:
The presence of bronchus-associated lymphoid tissue (BALT) and its size in humans largely depends upon age. It is detected in 35% of children less than 2 years of age, but absent in the healthy adult lung. Environmental gases or allergens may have an effect on the number of BALT. Lungs of rhesus macaque monkeys were screened by histology for the presence, size, and location of BALT after exposure to filtered air for 2, 6, 12, or 36 months or 12 and 36 months to ozone or 2, 12, or 36 months of house dust mite or a combination of ozone and house dust mite for 12 months. In the lungs of monkeys housed in filtered air for 2 months, no BALT was identified. After 6, 12, or 36 months, the number of BALT showed a significantly increased correlation with age in monkeys housed in filtered air. After 2 months of episodic house dust mite (HDM) exposure, no BALT was found. Monkeys exposed to HDM or HDM + ozone did not show a significant increase in BALT compared to monkeys housed in filtered air. However, monkeys exposed to ozone alone did show significant increases in BALT compared to all other groups. In particular, there were frequent accumulations of lymphocytes in the periarterial space of ozone exposed animals. In conclusion, BALT in rhesus monkeys housed under filtered air conditions is age-dependent. BALT significantly increased in monkeys exposed to ozone in comparison with monkeys exposed to HDM.
