Used in immunological research to quantify CD4 protein levels in biological samples. Commonly applied in studies related to T-cell function, immune response monitoring, and bovine viral infections such as bovine immunodeficiency virus (BIV). Supports research in veterinary immunology, vaccine development, and evaluation of immune system status in cattle. Enables high-throughput analysis of CD4 expression in cell cultures, serum, or plasma. Useful for assessing immune modulation in experimental treatments or disease models.