02399nas a2200169   4500008004100000245012600041210006900167260001300236300001100249490000700260520173200267100002301999700002002022700001702042700002102059856014902080       2007                        eng d00aAnti-Trypanosoma brucei activity in Cape buffalo serum during the cryptic phase of parasitemia is mediated by antibodies.0 aAntiTrypanosoma brucei activity in Cape buffalo serum during the  c2007 Oct  a1391-90 v373 aCape buffalo are reservoir hosts of African trypanosomes. They rapidly suppress population growth of the highly antigenically variable extracellular haemoprotozoa and subsequently maintain a cryptic infection. Here we use in vitro cultures of trypanosomes cloned from Cape buffalo blood during cryptic infection, as well as related and unrelated trypanosomes, to identify anti-trypanosome components present in cryptic-phase infection serum. Trypanosome clone-specific complement-dependent trypanolytic IgM and IgG arose after appearance of target trypanosomes during cryptic infection. Serum collected late in the cryptic phase of infection contained complement-independent growth-inhibitory IgG which varied in activity among target trypanosomes. Removal of protein A/G-binding IgG from the serum restored its capacity to support trypanosome growth in vitro. Recovered growth-inhibitory IgG reacted with the variable surface glycoprotein (VSG) of parasites most affected by it, and reacted with trypanosome common antigens, notably the endosome-restricted tomato lectin-binding glycoproteins (TL-antigens). The inclusion of purified TL-antigens in culture medium did not affect the trypanosome growth-inhibitory activity of immune Cape buffalo serum. In addition, hyperimmune rabbit IgG against TL-antigens showed little or no binding to intact trypanosomes and did not affect trypanosome growth in vitro although it did react strongly with TL-antigens and trypanosome endosomes. We conclude that antibodies, particularly clone-specific (putatively VSG-specific) antibodies are responsible for the anti-trypanosome activity of cryptic phase infection serum consistent with a dominant role in parasite control in Cape buffalo.1 aGuirnalda, Patrick1 aMurphy, Noel, B1 aNolan, Derek1 aBlack, Samuel, J  uhttps://www.umass.edu/veterinary-animal-sciences/research-faculty/publications/anti-trypanosoma-brucei-activity-in-cape-buffalo-serum-during-the