The effect of cryopreservation on antigen-presenting cells (APCs) is understudied. It is important to understand the effects of cryopreservation on these cells as they play a major role in immune responses, and they could be utilized in different clinical applications.

In this study, we compared fresh and cryopreserved PBMCs in regards of their general immune responsiveness and, furthermore, the effect of cryopreservation on the circulating APCs among PBMCs. We stimulated fresh and cryopreserved PBMCs (N = 6) with LPS or Poly(I:C).Cytokine production of PBMCs and expression of functional markers CD80 and ILT4 on major types of APCs, dendritic cells (DCs) and monocytes, were analysed. We also analysed whether cryopreservation affects different subtypes of DCs (plasmacytoid and myeloid DCs) differently.

Cryopreserved PBMCs produced less cytokines than fresh cells in response to stimulation, but the response profiles were comparable. Cryopreservation had also an effect on the relative proportions of APCs. Stimuli-induced responses were somewhat parallel but weaker than those observed in fresh cells.

This study suggests that the use of cryopreserved cells is more suitable in studies that assess general responses to stimuli instead of measuring exact levels of reactions. Thus, the interpretation and comparison of the results of different studies should not be done without considering the differences in cryopreservation techniques and their effects on PBMCs and, more specifically, on APCs.

冷冻保存对抗原呈递细胞（APC）的影响尚在研究中。重要的是要了解冷冻保存对这些细胞的作用，因为它们在免疫反应中起主要作用，并且可以在不同的临床应用中使用。

在这项研究中，我们比较了新鲜的和冷冻保存的PBMC的总体免疫反应性，此外，还研究了冷冻保存对PBMC之间循环APC的影响。我们 用LPS或Poly（I：C）刺激了新鲜和低温保存的PBMC（N = 6）。分析了PBMC的细胞因子产生以及主要类型的APC，树突状细胞（DC）和单核细胞上功能标记CD80和ILT4的表达。我们还分析了冷冻保存是否会不同地影响DC的不同亚型（浆细胞样和髓样DC）。

与刺激相比，冷冻保存的PBMC产生的细胞因子要少于新鲜细胞，但应答情况却相当。冷冻保存对APC的相对比例也有影响。刺激诱导的反应有些平行，但比新鲜细胞中观察到的弱。

这项研究表明，使用冷冻保存的细胞更适合用于评估对刺激的一般反应而不是测量确切反应水平的研究。因此，在不考虑冷冻保存技术的差异及其对PBMC，尤其是对APC的影响的情况下，不应对不同研究的结果进行解释和比较。