Table 1.

Effect of NP size on the immunological response

Size	Material	Context	Immunological response	Refs
1.5 nm	Gold	Listeria	AuNP–LLO (listeriolysin O peptide) plus Advax™ adjuvant induced LLO-specific T cell immunity and protection against Listeria challenge	[47]
2–50 nm	Gold	Foot and mouth disease	Specific antibodies were induced by 2, 5, 8, 12, and 17 nm FMDV plus cysteine (pFMDV)–AuNP conjugates. Maximal antibody titer was generated with 8–17 nm conjugates	[48]
10–100, 60–350, 400–2500 nm	Bilosome	Influenza	Larger bilosome particles with influenza A antigens elicited immune responses that had a significantly greater Th1 bias than the small particles	[83]
12 nm	Gold	Influenza	Matrix 2 protein (M2e)–AuNP conjugates induced M2e-specific IgG serum antibodies	[22]
20–123 nm	Polystyrene	Respiratory syncytial virus (RSV)	IFN-γ induction from CD8 T cells was limited to 40−49 nm beads, whereas CD4 T cell activation and IL-4 were induced by 93−123 nm beads	[78]
30–200 nm	Polystyrene	Tumor	Nanobeads of 40–50 nm effectively induced cellular responses by activating CD8+ T cells with IFN-γ production	[79]
40 nm	Gold	Tetanus toxoid	Enhanced tetanus toxoid (TT)-specific IgG (34.53×) and IgA (43.75×) was elicited by TT-ARE-CsAuNPs	[49]
100, 500 nm	PLGA	Nicotine	The 100 nm particles induced significantly higher antibodies than the 500 nm particles	[71]
200, 500, 1000 nm	PLGA	Bovine serum albumin	A greater IgG response was elicited by 1000 nm particle than by 200–500 nm particles	[66]
200–600 nm, 2–8 μm	PLA	Hepatitis B virus	Hepatitis B virus surface antigen (HBsAg) encapsulated in 2–8 μm particles generated more antibodies than 200–600 nm particles	[74]
220, 660, 1990 nm	PMMA Eudragit®	HIV	HIV TAT protein modified NPs of 220 or 630 nm elicit strong TAT-specific cellular immune response but weaker anti-TAT antibody response than NPs of 1.99 μm	[77]