Hi John. I didn't see this question until now, so maybe not relevant to answer anymore, but I'll give it a try. Lots of immunotox has been performed in both mouse and rats, but I believe still most in mice (I also did that). You should consider how you want to expose the animals (inhalation, intranasal/intratracheal instillation). Lots of nice work to estimate deposition after both inhalation and intranasal exposure has been performed in mice. Also, you should think about what you want to measure as endpoints. Colouring of inflammatory cells in bronchoalvelolar lavage fluid (BALF) can be performed in both species, but as soon as you want to phenotype cells by flow cytometry, measure cytokines in BALF or antibodies - a lot more reagents are available for the mouse. Also, more studies have investigated different immunological properties of different mice strains. Regards, Jitka

Thanks Jitka! Presently I am using Cell line. I appreciate your explanation, meanwhile I later find out that F-344 rat is good for quartz study , realy subceptible to quartz effects. I may be using that for further studies. regards, John