Immune Response in Cattle Following Immunization with A Heterologous Lumpy Skin Disease Virus Vaccine: A Longitudinal Study

Abstract

Lumpy skin disease (LSD) is a highly contagious disease of cattle. The samples (n= 240) were collected from 30 cattle and buffalo across five farms in potential risk regions of Sindh, Pakistan, employing stratified random sampling. Both young (≤ 1 year) and adult (≥ 1 year) animals and a control group comprising of non-vaccinated animals to compare immunity with the LUMPYVAC® vaccine. The immune response of cattle to heterologous lumpy skin disease virus (LSDV) vaccination was assessed by evaluating physical health, antibody production, and interferon-gamma (INF-ɣ) levels. Blood samples were collected from two groups: one consisting of animals recovered from clinical LSDV infections and the other consisting of vaccinated animals. Throughout the experimental period, no clinical signs or abnormalities were observed, with slight variations in body temperature noted. Before vaccination, animals showed antibody titers below the seropositive threshold of 30%. Following vaccination, cattle began to develop antibodies against LSDV 30 days post-vaccination, with young animals showing high antibody levels (80%) after the first dose and adult animals achieving 83.31% seropositivity. After two doses, antibody levels ranged from 51.72% to 94.35%. However, six months post-vaccination, a decrease in antibody levels was observed, with only 6.7% of younger cattle and 43.3% of older cattle retaining detectable antibodies. After 11 months, no younger cattle had detectable antibodies, while only 6.7% of older cattle showed low levels just above the threshold. Significant differences (p<0.05) were observed in antibody levels before vaccination and post-vaccination six months of vaccination. However, no statistically significant difference (p>0.05) was detected in antibody levels from 1 month to 11 months post-vaccination. Interferon-gamma (INF-ɣ) production was also monitored, revealing that vaccinated cattle produced 100 pg/ml of INF-ɣ against LSDV 30 days post-vaccination. The first immunization resulted in low INF-ɣ concentrations (100 pg/ml), while the second dose six months later induced peak INF-ɣ levels of 1400 pg/ml in young animals and 1100 pg/ml in adults. Statistical difference (p<0.05) was recorded in increase Gamma- interferon (INF-ɣ) in both Groups following vaccination 1 month and 6 months. However, no statistically significant difference (p>0.05) was observed for the decrease in gamma-interferon (INF-ɣ) at 11 months post-vaccination. In summary, vaccination against LSDV triggered an immune response in cattle, marked by increased antibody production and interferon-gamma (INF-ɣ) levels. The research highlights the efficiency of the vaccine in the induction of a strong immune response in dairy animals, and the requisite for being used vaccination to maintain an immune response against LSD.