Other organs involved:

Tonsils and adenoids -

They are two lumps of tissues, on either sides in the throat, inserted in a pocket beside the palate (that's the roof of the mouth). The low edge of every single tonsil is near the tongue...way at the back of the throat. The adenoids really are a single clump made of tissue behind the nose area (nasopharynx). They're situated (in the adult) around the backside wall structure of the throat (pharynx)...about 1 inch over the uvula (the small teardrop shaped little bit of tissues that dangles down in the center of the soft palate). Even though adenoids and tonsils have comparable purpose, i.e. trapping viruses and bacteria, they're entirely independent immune organs. 

Source: Organs of the immune system from immune-system-expert.com

Link: https://www.immune-system-expert.com/immune-organs.html
 

Peyer’s patches -

the nodules of lymphatic cells that combine to make patches or bundles and appear generally only within the lowest part (ileum) of your small intestine; they're called for that 17th-century Switzerland anatomist Hans Conrad Peyer. Saying that in a different way, they could be thought as patches of nodules, in the small intestiness walls; agminated glands. 

Source: Organs of the immune system from immune-system-expert.com 

Link: https://www.immune-system-expert.com/immune-organs.html

Appendix -

 It's a thin, dead-end tube measuring about three-to-four inches in length and it hangs from the cecum (which is end in the large intestine). Even though it's typically called the "appendix," the actual term for it is "vermiform appendix."

During the past, the appendix was regarded as not having any purpose in the body or as not currently being among the immune organs. Today, it is stated, often, that this takes on a task in the body's defense mechanisms because its surfaces incorporate aggregated lymphoid tissues. researchers say the appendix assists in supporting the immunity process in 2 approaches. It will help tell the lymphocytes exactly where they have to head over to attack infection and it also enhances the massive intestine's defenses to a range of drugs and foods.

Source: Organs of the immune system from immune-system-expert.com 

Link: https://www.immune-system-expert.com/immune-organs.html

Reference of this article:

Organs of the immune system from immune-system-expert.com

Link:  https://www.immune-system-expert.com/immune-organs.html