GAS-M1 (IMAGE) University of California - San Diego Caption Group A <em>Streptococcus</em> bacteria (red) coat their surfaces with M1 proteins (white), which "stiff-arm" natural antibiotics produced by the human body. Credit UC San Diego Health Usage Restrictions Use photo credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.