The sulphated polysaccharides extract ulvans from Ulva armoricana limits Marek’s disease virus dissemination in vitro and promotes viral reactivation in lymphoid cells

Abstract

Background Marek’s disease (MD) is a highly contagious lymphoproliferative disease of chickens caused by an alphaherpesvirus, Marek’s disease virus (MDV). MD is presently controlled by systematic vaccination of animals, which protects efficiently against the development of clinical disease. However, MDV vaccines do not prevent the multiplication and spread of MDV field strains and may favor the emergence of strains with increased virulence. Therefore, MDV persists to be a major problem for the poultry industry and the development of new alternative strategies to control MDV is needed. Seaweed extracts have previously been shown to exert immunomodulatory and antiviral activities, especially against herpesviruses. The objective of the present study was to explore the effect of Ulva armoricana extracts on MDV infection in vitro. Results We could demonstrate that the ulvan extract as well as its vitamin-enriched formulation reduce the viral load by about 80% at 24 h post-infection in infected chicken fibroblasts at concentrations that are innocuous for the cells. We also observed a substantial decrease in MDV plaque size suggesting that ulvans impede MDV cell-to-cell spread in vitro. Moreover, we showed that ulvan extract could promote MDV reactivation in lymphoid cells. Conclusions Our data provide the first evidence that the use of the ulvan extract could be a good alternative to limit MDV infection in poultry.

Immunopotentiating effect of lentinan on chicks and its inhibitory effect on Marek's disease virus infection

“…Despite being vaccinated against MD, there have been numerous cases in which wild strains of MDV have managed to bypass the vaccine's immune protection. Therefore, many farms and research institutes have explored the use of other complementary measures such as plant polysaccharides to enhance the prevention and control of MDV infection ( Bussy et al, 2022 ).…”

Immune escape of avian oncogenic Marek’s disease herpesvirus and antagonistic host immune responses

“…Considering that the currently used MD vaccines cannot prevent the infection and spread of MDV epidemic strains, additional alternative strategies for the efficient control of this disease are needed. In a recent study 132 , the sulfated polysaccharide extract ulvans from Ulva armoricana was verified to exert antiviral activity by limiting the replication/dissemination of viruses or stimulating the innate immune system of hosts, which may be an alternative to drug therapy for MDV infection. A study on the differential expression of purinergic receptors (PRs) in response to MDV infection and disease progression has demonstrated their crucial role in the process of https://doi.org/10.1038/s41541-024-00905-0 disease; PRs may provide another potential target for MD therapy 133 .…”

Marine-Sulfated Polysaccharides Extracts Exhibit Contrasted Time-Dependent Immunomodulatory and Antiviral Properties on Porcine Monocytes and Alveolar Macrophages

“…This is not the first time that antiviral effects have been demonstrated for algal extracts. Indeed, previous reports show direct and indirect antiviral effects of algal extracts, mostly due to sulfated polysaccharides, such as ulvan for green algae or carrageenan, galactan and agar for red algae (for review see [ 40 ]), acting against several viruses such as human metapneumovirus (HMPV), Newcastle disease virus (NDV), Marek’s disease virus (MDV) and human immunodeficiency virus (HIV) [ 41 , 42 , 43 , 44 ].…”