The various strains of borrelia that cause infection are tenacious, pleomorphic (shape-shifting) pathogens which are a bit of a cross between bacteria and fungus. Anyone infected by them understands the war they wage in the human body and mind.
This excellent review shows the ability of spirochetes to evade the innate immune system. One way they do this is by binding with human compliment regulators to prevent complement-mediated killing.
The author states that up to five distinct outer surface lipoproteins (CRASP) have been identified but that there have been various names given historically that cause confusion. Please see table in the link above to understand this better.
The take home: borrelia is tough to kill and effectively evades the human immune system. It can morph between spirochete, cell wall, and non cell wall forms, necessitating combination antibiotic treatment that targets every form.
For more information on treatment, read: https://madisonarealymesupportgroup.com/2016/02/13/lyme-disease-treatment/ and https://madisonarealymesupportgroup.com/2016/08/09/dr-paul-duray-research-fellowship-foundation-some-great-research-being-done-on-lyme-disease/ (The last link outlines microbiologist Tom Grier’s work showing spirochetes hiding in parasitic worms inside the human body, necessitating anthelmintics to effectively kill them).