Peste des petits ruminants (PPR) is one of the most important viral diseases with serious socio-economic implications and is estimated to cause loss to the tune of 1, 800 million INR (39 million US$) in India . PPR is a highly contagious, world organization for animal health (OIE) notifiable and transboundary viral disease of small ruminants, especially sheep and goats, characterized by necrotizing, erosive stomatitis, enteritis and pneumonia . The causative agent, PPR virus (PPRV), has been classified under the family Paramyxoviridae, order Mononegavirales and genus Morbillivirus .
The virus causes severe destruction of lymphoid cells leading to immunosuppression in the host . Cytokines play a major role in shaping immune response as TH-1/type-1 cytokines elicit predominantly cell-mediated immunity (CMI), whereas TH-2/type-2 cytokines elicit predominantly humoral immunity. Most of the cytokine studies were carried out on Measles Virus (MV).
Experimental PPR infection in goats can lead to marked suppression of host immune responses accompanied by severe leucopenia , but the mechanism is not understood. However, it can be speculated that infection interferes with host immune effector cells mediated by cytokines. A study of the relationship between cytokine expression and kinetics of antigen and antibody response in PPR affected animals has not yet been attempted. Therefore the current investigation was undertaken to correlate the cytokine profile and kinetics of antigen and antibody in PPR infected and vaccinated goats. To the best of the authors' knowledge, this is the first report on the cytokine profile in PPR infected goats.
Cytokines Expression Profile and Kinetics of Peste des petits ruminants Virus Antigen and Antibody in Infected and Vaccinated Goats
- Received Date: 06 January 2012
- Accepted Date: 28 May 2012
Abstract: The present study deals with the co-ordination of cytokine (IL-4 and IFN-γ) expression and kinetics of peste des petits ruminants (PPR) virus antigen and antibody in PPRV infected and vaccinated goats. The infected animals exhibited mixed cytokine (both TH1 and TH2) responses in the initial phase of the disease. The infected and dead goats had increased IFN-γ response before their death; while IL-4 remained at the base level. The cytokine expression in recovered animals was almost similar to that of vaccinated ones, where a unique biphasic response of IL-4 expression was observed with an up-regulation of IFN-γ on 7th days post vaccination (dpv). Analysis of PPR virus antigen and antibody kinetics in different components of blood from infected and vaccinated animals revealed that the PPR virus antigen load was highest in plasma followed by serum and blood of the infected animals, whereas vaccinated animals showed only marginal positivity on 9th dpv. The antibody titer was high in serum followed by plasma and blood in both vaccinated and infected animals. Therefore, it is inferred that the presence of antigen and antibody were significant with the expression of cytokine, and that a decreased response of IL-4 was noticed during intermediate phase of the disease i.e., 7 to 12th days post infection (dpi). This indicates the ability to mount a functional TH2 response after 14th dpi could be a critical determinant in deciding the survival of the PPR infected animal.