Development of Neospora caninum Cultured with Human Serum In Vitro and In Vivo

Abstract

Because there has been no report of symptomatic Neospora caninum infection in humans, we examined the effect of human serum on the parasite's growth in either a bovine angioendothelial cell or Caco-2 cell culture in vitro and in immunocompromised mice in vivo. There was no difference in intracellular parasite numbers between cells incubated with human serum at 24 hr after challenge and those incubated with fetal bovine serum (FBS), which has no titer for the anti-N. caninum agglutination antibody test. Serum of sheep infected with N. caninum, which has the anti-N. caninum antibody, reduced the numbers of the intracellular parasite significantly. We also showed that there was no inhibitory effect on the intracellular multiplication of the parasite in cells incubated with human serum through incorporation of 3H-uracil. CB-17 scid mice administered human serum daily and challenged with N. caninum died on day 20 or 22 after challenge, when large numbers of parasite clusters were found in the brain, oviduct, adrenal gland, lung, stomach, spleen, skeletal muscle, pancreas, and mesenteric lymph nodes. Scid mice administered FBS survived until the end of the experiment. These results suggest that adult human serum may have no inhibitory effect on the development of N. caninum in vitro and in vivo.

Seroprevalences of Toxoplasma gondii and Neospora caninum infections in Jordanian women who had a recent spontaneous abortion

“…caninum-IgG seropositivity is associated negatively (OR= 0.1) with fetal loss during the second half of pregnancy. A significant inhibitory effect on the intracellular multiplication of the N. caninum in cells was demonstrated in vitro using sheep serum which had anti-N. caninum antibodies (Omata et al, 2005). N. caninum-IgM antibodies are detectable within two weeks of infection, while N. caninum-IgG requires several weeks, peaking six months later (Khan et al, 2020).…”

Cellular and immunological basis of the host-parasite relationship during infection withNeospora caninum

“…This process has been initially investigated in vitro using bovine aorta endothelial cell monolayers (Hemphill et al 1996), and later for many other cell types (reviewed by Hemphill et al 2004). While human cells or cell lines such as human foreskin fibroblasts, Hela cells and Caco2 (colon cancer) cells are readily infected in vitro, there is no conclusive evidence that N. caninum actually infects humans (Peterson et al 1999 ;Tranas et al 1999 ;Graham et al 1999 ;Dubey, 2003 ;Omata et al 2005).…”