Skin cells  At a Glance A type of skin cell called a dermal fibroblast can make an antimicrobial compound called cathelicidin in response to infection by acne-causing bacteria. The results suggest approaches that could lead to improved treatments for acne.   Microscopic image of an inflamed pimple with cathelicidin stained red, fat cells stained green and the nuclei of every cell stained blue. Because cathelicidin is produced from fat cells, their staining merges together.  Gallo lab, University of California, San Diego. Acne starts within the skin’s hair follicles. Hair, oil, and dead skin cells can come together to plug the follicle, causing a clogged pore. This creates the right conditions for bacteria that normally live on the skin to thrive. The body’s immune system then attacks the bacteria, causing the pain and swelling of a pimple. A class of drugs called retinoids are effective in treating acne. However, they can cause side effects. These include birth defects if someone beco