LOU/C, Rat Strain

**Semantic type:** Mammal

**Definition:** Develop spontaneous plasmacytomas after about 8 months of age, with an incidence of about 30% in males and 16% in females. These develop rapidly, and may be detected by palpation. They usually develop in the ileocoecal lymph nodes, and about 60% of them synthesis monoclonal immunoglobulins (Bence-Jones proteins) of IgG1 (35%), IgE (36%) or IgA classes.