Abstract: The CD47 mimic protein of Borrelia burgdorferi is identified as p66 protein. Blocking the p66 protein on the pathogen Improves the immune response of an infected individual, and allows a more complete and/or more rapid resolution of Borrelia infection. The disclosure provides a method of inhibiting or treating an infection by a Borrelia pathogen, the method comprising administering an effective amount of an anti-p66 agent that reduces binding of p66 on the pathogen to signal regulatory protein a (SIRPa) on a phagocytic cell, where the agent (i) specifically binds to p66, or (ii) is a p66 polypeptide or derivative thereof.

Abstract: Methods are provided for treating a subject for an infection by a pathogen expressing a CD47-like mimic protein on its surface.

Abstract: Prolonged exposure of CD8+ T cells to antigenic stimulation leads to a state of diminished function, termed exhaustion; during exhaustion there is a subset of functional CD8+ T cells defined by surface expression of SIRP(alpha) protein. On SIRP+ CD8+ T cells, expression of coinhibitmy receptors is counterbalanced by expression of co-stimulatory receptors and it is only these SIRP+ cells that actively proliferate, transcribe IFNg and show cytolytic activity. Therapeutic blockade of PD-L1 or other inhibitory receptors to reinvigorate exhausted CD8+ T cells expands the cytotoxic subset of SIRP+ CD8+ T cells.

Abstract: Methods and kits are provided for determining whether an individual is responsive to therapeutic CD47 blockade. Specifically, the disclosure provides methods of determining whether a cell or cell population is responsive to therapeutic CD47 blockade, the method comprising: assaying a cell sample from an individual to determine (a) the level of expression of signal regulatory protein alpha (SIRPalpha) on phagocytic immune cells, or (b) the genotype of the individual at a nucleotide polymorphism (SNP) associated with SIRPalpha expression. Further disclosed are SNPs associated with SIRPalpha expression.

Abstract: Compositions and methods are provided for diagnosis of infections. The patterns of antibody isotype, subtype and glycosylation provide for a signature pattern that can identify infective agents and patient response to infection. Patients likely to benefit from therapeutic intervention can be discriminated from patients that have a low probability of responsiveness. Therapies are also provided.