The invention provides molecules containing nucleic acid sequences for fragments of LPS-induced TNF-.alpha. factor (LITAF) and vectors containing these sequences. Also provided are molecules that contain the peptide sequence SQTWREPGAAGSPFHL, or homologs thereof. Such molecules may be useful in the treatment of diseases that relate to the expression of TNF-.alpha., where treatment involves the modulation of this expression. The invention also provides methods for identifying compounds that inhibit or enhance the transcription of TNF-.alpha..