The invention relates to T. cruzi trans-sialidase (TS) and to the neurotrophic and IL-6 secretion-inducing activities of the protein. TS, neurotrophic variants and/or neurotrophic peptides based upon the sequence of TS can be administered to a mammal to directly or indirectly provide neurotrophic support for neurons. A mammalian neurotrophic factor (e.g., CNTF, LIF) can be co-administered with the TS, neurotrophic variant and/or neurotrophic peptide. TS, IL-6 secretion-inducing variants and/or IL-6 secretion-inducing peptides based upon the sequence of TS can be administered to a mammal to induce the secretion of IL-6. TS, active variants and/or active peptides can be administered to a mammal having an acquired or congenital condition characterized by neuronal degeneration or to a mammal that has experienced trauma to the brain, spinal cord or peripheral nerves. The invention also relates to neurotrophic and IL-6 secretion-inducing variants of TS and to neurotrophic and IL-6 secretion-inducing peptides. The invention also relates to compositions comprising TS, active variants thereof and/or active peptides and a physiologically acceptable carrier.