BCG vaccine bacilli that seemed less virulent, and changed the course of their research to see if repeated subculturing would produce a strain that was attenuated enough to be considered for use as a vaccine. The BCG strain was isolated after subculturing 239 times during 13 years from virulent strain on glycerine potato medium. The research continued throughout World War I until 1919, when the now avirulent bacilli were unable to cause tuberculosis disease in research animals. Calmette and Guerin transferred to the Paris Pasteur Institute in 1919. The BCG vaccine was first used in humans in 1921. Public acceptance was slow,
A2261-BCG stars, but is mysteriously diffuse, giving it a large core. On September 10, 2012, using Hubble Space Telescope's Wide Field Camera 3, scientists found out that there was no supermassive black hole present in the center. This may be the likely cause of its diffuse and large core, but it contradicts modern galactic evolutionary theories. A huge cD galaxy like A2261-BCG would be expected to have a supermassive black hole concentrated at its center. A2261-BCG A2261-BCG (short for Abell 2261 Brightest Cluster Galaxy) is a huge elliptical galaxy in the cluster Abell 2261. One of the largest galaxies known, A2261-BCG