In this study, we focused on the effects of obesity and T2D on PMs since macrophages play a key role in defense against invading pathogens.24 For example, it has been shown that infection susceptibility to Mycobacterium tuberculosis and Streptococci spp correlates with a decreased NO and TNF production by macrophages.25 26 We also determined whether the HFD-induced effects were reversible after weight loss because it is not clear which obesity-related complications will resolve after weight loss and which need additional treatment. Here, TNF is linked to obesity due to melanocortin 4 receptor deficiency.