Can bottled lemon juice boost your immune system?

Hi, my friend has the flu. I saw him at school lunch and at recess. He did'nt cough or sneeze, but I'm worried I will catch it. I sat diagonal from him at the lunch table, and near him outside. This was when the flu was just in the beginning stages. I drink lemon juice in seltzer all of the time, but I usulally put maybe 1/4 cup of lemon juice to 1 Cup seltzer (trust me it tastes real concentrated) I drink it a few times a day to boost my immune system. It isn't freshly squeezed though, its Price Rite bottled Lemon Juice. So, do you think bottled lemon juice has the same immune boosting benefits as freshly squeezed, and do you think I'll get the flu? I'm 13 and just starting 8th grade.