Most of the downregulated DE genes in the TB model group were related to cellular structural proteins and cellular functional proteins (Table 3), in which the structure and function proteins of alveolar epithelial cells account for a large proportion, for example, Sftpc, Sftpb, Sftpd, Sftpa1, Wfdc2, Sec1413, Postn, Cldn5, Aqp5, Emp2, and Foxf1, and so forth. The gene discussed is CLDN5; the disease is tuberculosis.