Prevalent human coxsackie B-5 virus infects porcine islet cells primarily using the coxsackie-adenovirus receptor.
BACKGROUND
We have previously demonstrated that transplanting porcine encephalomyocarditis virus (EMCV)-infected porcine islet cells (PICs) results in transmission of the virus to recipient mice, which is manifested by acute fatal infection within 5 to 8 days. Here, we determined PIC susceptibility to a related and highly prevalent human picornavirus, coxsackie B-5 virus (CVB-5).


METHODS
PICs were inoculated with CVB-5 in vitro for up to 96 hours and infectivity, level of virus replication, and cellular function determined. Subsequently, monoclonal and polyclonal antibody blocking experiments were used to investigate the receptor CVB-5 uses to enter PICs, and the ability of CVB-5-infected islets to reverse diabetes analyzed in mice.


RESULTS
Adult pig islets inoculated with CVB-5 in vitro showed a typical picornaviral replication cycle with a 2-h lag phase followed by a 4-h exponential phase during which the virus titer increased by 4 logs. However, CVB-5 was less cytolytic to PICs than EMCV, resulting in a persistent productive infection lasting for up to 96 h, with minimal evidence of cell lysis. Double immunostaining confirmed the presence of CVB-5 antigens in insulin-producing islets. Infection of PICs in the presence of antibodies against human coxsackie-adenovirus receptor (CAR) resulted in near complete blockage in production of infectious virus particles whereas blocking with anti-porcine decay-accelerating factor (DAF, also called CD55) or anti-porcine membrane cofactor protein (MCP, also called CD46) only slightly decreased the number of infectious CVB-5 particles produced. Immunofluoresence staining showed CAR and MCP expression on the islet surface, but not DAF. Transplanting CVB-5-infected PICs into diabetic C57BL/6 mice resulted in reversal of diabetes.


CONCLUSIONS
Although PICs are susceptible to human CVB-5, the infection does not appear to affect xenograft function in vitro or in vivo in the short term.
Pathobiology Graduate Program, Veterinary Science Department, Pennsylvania State University, University Park, PA, USA.
Suzanne E
SE
Myers
Laurie
L
Brewer
Daniel P
DP
Shaw
Wallace H
WH
Greene
Brenda C
BC
Love
Bernhard
B
Hering
O Brad
OB
Spiller
M Kariuki
MK
Njenga
D000818:Animals; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral / Q000097:blood; D003921:Diabetes Mellitus, Experimental / Q000628:therapy*; D029822:Enterovirus B, Human / Q000302:isolation & purification*; D004769:Enterovirus Infections / Q000453:epidemiology*; D006801:Humans; D007515:Islets of Langerhans / Q000821:virology*; D016381:Islets of Langerhans Transplantation; D051379:Mice; D008810:Mice, Inbred C57BL; D009500:Neutralization Tests; D011991:Receptors, Virus / Q000276:immunology / Q000378:metabolism; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D013552:Swine; D014183:Transplantation, Heterologous
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D011991:Receptors, Virus; C085301:adenovirus receptor