Cell Killing by Anti-HIV Immunoconjugates Demonstrates Overlap among Metabolic and Transcriptional Pathways of Death and Activation

In testing monoclonal antibody (mAb)-based therapies to eradicate the persistent reservoir of HIV infection, we compared the killing of HIV-infected cells by different forms of cytotoxic immunoconjugates (CICs) targeted by the same mAb. CICs consisted of the anti-HIV mAb 7B2 conjugated to either deglycosylated ricin A chain (dgA) or to the anthracycline derivative PNU-159682. At intervals up to 24 h post treatment intracellular metabolites were identified and quantified by 1H nuclear magnetic resonance spectroscopy; the transcriptome was analyzed by RNA-Seq. Six h post treatment, 7B2-dgA elicited both metabolic and transcriptional alterations, whereas 7B2-PNU treated cells did not differ from untreated cells. By 24 h, both 7B2-dgA and 7B2-PNU treated cells differed markedly from untreated. Among the earliest changes following both treatments were activation of gene pathways for apoptosis, intracellular signaling, and those associated with immune activation. Elevated intracellular levels of branched chain amino acids, typically observed with immune activation, were also observed. There were also changes unique to each treatment. The results demonstrate close relationships of the events associated with immune cell activation and those of cell death, and suggest where these processes may diverge. Differences between the two forms of CIC were also noted, the clinical significance of which remains to be investigated.