Antje Ksienzyk Department of Gene Regulation and Differentiation aks08@helmholtz-hzi.de

Antje Ksienzyk

Department of Gene Regulation and Differentiation

aks08@helmholtz-hzi.de

Replication in first organPrimary viremia

Secondary viremia

Replication

dissemination

other organs

model of systemic virus infection

Infection

MCMV

-Herpesviridae herpesvirus

-Cytomegalovirus-MCMV: mouse cytomegalovirus

HCMV :major risk factor for immunoincompetent and immunocompromised patients

(AIDS patients and organ transplant recipients)

MCMV: represents the rodent model

MCMV replicates in a broad spectrum of cell types: vascular endothelial cells and

hepatocytes

The Cre-Loxp system

The used Cre-Loxp system

MCMV- flox and –rec replicate in the same manner

Experimental set-up

106 PFU of MCMV flox

Analyses of MCMV-rec and MCMV-flox plaque forming units

EC and HC are important cell types for MCMV replication

Tie2-cre: Cre under control of Tie2 (endothelial tyrosinkinase receptors: only in EC) promoter in vascular ECAlb-cre: Cre under control of albumin promoter in hepatocytes

Hepatocytes are the main producer cell type

Hepatocytes derived MCMV-rec do not disseminate from the liver to other organs (alb-cre)

Alb-cre

Influence of route and dose

Amount of cre expression, the route and dose of infection have no influence on the results

Alb-cre

Virus isolation out of liver

i.v. injection

C57BL/6

Hc-derived MCMV has potential to replicate in spleen and lung

Bidirectional spread of MCMV between EC and Hc

EC and Hc produce virus which can infect neighboring cellsNo explanation that Hc derived virus can’t disseminate

Tie2-cre: MCMV from EC to HcAlb-cre: MCMV from Hc to EC

MCMV infection is controlled by CD3+ cells

Elimination of MCMV is correlated with liver infiltrating T-cellsReason for dissemination stop?

Immunosuppression has no influence on Hc- derived virus dissemination

1 untreated2, 3 -irradiation4 immune suppression by cyclophosphamide 5 proinflammatory stimuli. Con A

No increase of dissemination after immune suppression and proinflammatory stimuli

- untreated+ immunodepleted

summary

- Hepatocytes and EC are target cells of MCMV in vivo (replication)

- HC are important target cells but are not involved in virus dissemination

-Infected EC contribute to viremic dissemination by serving as transport vehicle and

by uptake and release of virus

- Hc derived MCMV never leads to a second viremia (unlike to former publications)

-But what is the reason for that?

-Independent on immune cells or irradiation

-Independent on ability to infect other cells

- IFN???