DOES EXPOSURE TO PCB 153 ALTER THE IMMUNOLOGICAL RESPONS OF BALB/C MICE TO A PATHOGEN?

Summary

Persistent organic pollutants accumulate in the Arctic and studies indicate that exposure to PCBs lead to inadequate immune function and risk of disease development. PCB 153 is the congener found at the highest levels in the Arctic. BALB/c mice were inoculated intra peritoneally with Brucella pinnipedialis or Brucella suis 1330. Two of four groups á 20 mice were exposed to PCB 153 (588 ug/kg mice/day) in the food. Mice were killed at one, three, six and twelve weeks post infection. The number of colony forming units (CFU) in spleen, liver and kidney was evaluated. B. pinnipedialis was able to establish an infection but at a much lower level than B. suis 1330. Our study showed that exposure to PCB 153 did not alter the number of CFU with either strain, indicating that the course of the infection was not altered by the exposure to PCB 153. The spleens were aseptically removed and splenocytes were cultured in vitro while stimulated with Concanavalin A. RNA was extracted from the splenocytes. We validated the housekeeping gene β-actin with the ΔΔCt-method for gene expression studies with qRT-PCR for the cytokines IL-4, IL-10 and IFN-γ. Sequencing of the PCR-products and BLAST analysis confirmed the identity of the cytokines. Our study thus offers a validated method for evaluation of immunological response in this model. Preliminary results have not yet confirmed a relevant in the immunological response between the PCB-exposed and non PCB-exposed groups.