The code "MS" stands for "Mud & Snow". The manufacturer wants to indicate that the car tyre can take a beating. The tyres are deemed suitable for maintaining sufficient grip in wet, cold and muddy conditions.
Unfortunately, this does not mean that your truck tyre is also officially an approved all-season tyre or even a winter tyre.
Info
In order to ensure the safety of real winter countries, the marking 3PMSF (Three Peak Mountain Snow Flake) has been established; the recognizable Alpine symbol of a snowflake on the background of the three peaks. This is the only reliable symbol that confirms winter properties of the tire. Models with this marking are suitable for demanding winter weather and they do not lose their properties at temperatures below zero. The standard and the EU-controlled mark 3PMSF is a guarantee that the product meets the conditions of the strict tests and is suitable for use in extreme weather conditions.