The basis of T cell stimulation is via the specific interaction of an immunogenic peptide in complex with MHC by a T cell receptor. Other co-stimulatory molecules such as CD80, CD86 on antigen presenting cells, are recognised by T cells via CD28 and CTLA-4 which results in T cell activation. In recent years the identification of checkpoint markers such as PD-L1, PDL2 on antigen presenting cells, epithelial cells etc and their interaction with PD-1 on activated T cells results in apoptosis of T cells and immune escape mechanisms, in the case of cancer. The role of checkpoint markers in a range of disorders including autoimmune disorders, inflammatory disorders and cancer are being studied with a plethora of information being published in the last 5 years. In addition, peptide alterations of T cell epitopes with 1-2 amino acid mutations can have drastic effects on the outcome of this recognition. Such peptides are termed, altered peptide ligands that can act as modulators of immune responses as they can down-regulate or upregulate responses. Over the last 30 years, there has also been an emphasis on carriers, adjuvants, and delivery systems to modulate immunity in vitro, in vivo in animal models of disease and in human clinical trials. With this information we have develop several immune modulators / therapeutics / vaccines for cancer, with phase I, II and pilot phase III human clinical trials; one having 25 years clinical follow-up; for MS currently in phase I human clinical trial; and several immune modulators for type-1 diabetes and methamphetamine (ice) drug addiction; all of which will be discussed in the presentation.