Dr.Manna's Ph. D. research work was carried out in the laboratory of Immunobiology, Indian Institute of Chemical Biology, Jadavpur University, Calcutta. During this period his research was focussed on the area of Immunology (Cytokine mediated immunoregulation). Interleukin-8, a neutrophil chemotactic cytokine largely involves in neutrophil-driven acute and chronic inflammatory diseases like rheumatoid arthritis, asthma, psoriasis and gout where chemoattracted neutrophils release several toxic oxygen radicals and proteolytic enzymes which damage the surrounding host tissues causes severe pain of patients. Their study suggested that a polyene antibiotic, hamycin reduced IL-8 mediated chemotactic responses of neutrophil which might have potential immunomodulator for alleviation of inflammatory distress. Soon after the thesis submission he joined Prof. Bharat B. Aggarwal's group at Department of Molecular Oncology, MD Anderson Cancer Center (MDACC), University of Texas, Texas, USA as a post-doctoral fellow to work on the role of ROI on TNF-mediated signaling molecules specially the kinases like JNK, MAPK, IKKs, LcK and transcription factors like NF-kB, AP-1, Sp-1, Oct-1 related to Apoptosis. He was involved on IL-4 mediated TNF receptor down-regulation which protect the cells from TNF induced cytotoxicity. His interests include receptor mediated cell signalling and apoptosis.