Abstract
Canine red blood cells were divided into a positive type (C type) and a negative type (c type) by a agglutination test with Clerodendron trichotomum lectin (CTL). Blood cells changed from c to C type after suffering from mammary tumor were named cm. The c type blood cells treated with neuraminidase were named cn. These red blood cells were studied with flow cytometry using a directly fluoresceinated CTL. Positive percents of C type, cm type, and cn type were 49.3%, 43.8% and 81.0% respectively. While C showed one peak in histogram, cm showed two peaks. The positive peak in the cm blood cells suggested an appearance of a new blood cell population with a novel sugar chain structure after suffering from the tumor.